void-packages/srcpkgs/electron7/files/patches/chromium-003-upstream_move_child_process_log.patch.patch

From 726cbfcfaa521e9e5098829195a7d9a9c19ca391 Mon Sep 17 00:00:00 2001
From: Joe Mason <joenotcharles@google.com>
Date: Wed, 4 Dec 2019 18:15:36 +0000
Subject: [PATCH] Move child process log capture to a ChildProcessLogger class.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Update comments to clarify how the child process log interacts with
ScopedLogging.

Use the new class to capture logs in cleaner_test.cc,
secure_dll_loading_test.cc and proto_chrome_prompt_ipc_unittest.cc.

R=​proberge

(cherry picked from commit 063600229fb7dc472ff66839ba2657bf99b98850)

Bug: 1030333
Change-Id: I88f538ff360bb8ed9da6743dc5d6c4b263af992c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1947986
Commit-Queue: Joe Mason <joenotcharles@chromium.org>
Reviewed-by: proberge <proberge@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#721184}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1949631
Reviewed-by: Joe Mason <joenotcharles@chromium.org>
Cr-Commit-Position: refs/branch-heads/3904@{#914}
Cr-Branched-From: 675968a8c657a3bd9c1c2c20c5d2935577bbc5e6-refs/heads/master@{#693954}
---
 chrome/chrome_cleaner/ipc/BUILD.gn            |  1 +
 chrome/chrome_cleaner/ipc/ipc_test_util.cc    | 98 +++----------------
 chrome/chrome_cleaner/ipc/ipc_test_util.h     | 17 ++--
 .../ipc/proto_chrome_prompt_ipc_unittest.cc   | 26 +++--
 chrome/chrome_cleaner/test/BUILD.gn           |  3 +
 .../test/child_process_logger.cc              | 90 +++++++++++++++++
 .../test/child_process_logger.h               | 62 ++++++++++++
 chrome/chrome_cleaner/test/cleaner_test.cc    | 14 ++-
 .../test/secure_dll_loading_test.cc           | 57 ++---------
 9 files changed, 207 insertions(+), 161 deletions(-)
 create mode 100644 chrome/chrome_cleaner/test/child_process_logger.cc
 create mode 100644 chrome/chrome_cleaner/test/child_process_logger.h

diff --git a/chrome/chrome_cleaner/ipc/BUILD.gn b/chrome/chrome_cleaner/ipc/BUILD.gn
index 03fddfd8736e1..4d81803a24df6 100644
--- a/chrome/chrome_cleaner/ipc/BUILD.gn
+++ b/chrome/chrome_cleaner/ipc/BUILD.gn
@@ -77,6 +77,7 @@ source_set("ipc_test_util") {
     "//base/test:test_support",
     "//chrome/chrome_cleaner/ipc:sandbox",
     "//chrome/chrome_cleaner/logging:common",
+    "//chrome/chrome_cleaner/test:test_util",
     "//mojo/public/cpp/system",
     "//sandbox/win:sandbox",
     "//testing/gtest",
diff --git a/chrome/chrome_cleaner/ipc/ipc_test_util.cc b/chrome/chrome_cleaner/ipc/ipc_test_util.cc
index 0d03a6870fb07..ea2bb2145bfdd 100644
--- a/chrome/chrome_cleaner/ipc/ipc_test_util.cc
+++ b/chrome/chrome_cleaner/ipc/ipc_test_util.cc
@@ -12,14 +12,10 @@
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
-#include "base/files/file_util.h"
-#include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
 #include "base/process/launch.h"
 #include "base/rand_util.h"
 #include "base/strings/string_number_conversions.h"
-#include "base/strings/string_piece.h"
-#include "base/strings/string_split.h"
 #include "base/test/multiprocess_test.h"
 #include "base/test/test_timeouts.h"
 #include "base/win/win_util.h"
@@ -34,11 +30,8 @@ constexpr char kMojoPipeTokenSwitch[] = "mojo-pipe-token";
 
 class MojoSandboxSetupHooks : public SandboxSetupHooks {
  public:
-  explicit MojoSandboxSetupHooks(
-      SandboxedParentProcess* parent_process,
-      base::win::ScopedHandle child_stdout_write_handle)
-      : parent_process_(parent_process),
-        child_stdout_write_handle_(std::move(child_stdout_write_handle)) {}
+  explicit MojoSandboxSetupHooks(SandboxedParentProcess* parent_process)
+      : parent_process_(parent_process) {}
   ~MojoSandboxSetupHooks() override = default;
 
   // SandboxSetupHooks
@@ -50,8 +43,7 @@ class MojoSandboxSetupHooks : public SandboxSetupHooks {
     parent_process_->CreateMojoPipe(command_line, &handles_to_inherit);
     for (HANDLE handle : handles_to_inherit)
       policy->AddHandleToShare(handle);
-    policy->SetStdoutHandle(child_stdout_write_handle_.Get());
-    policy->SetStderrHandle(child_stdout_write_handle_.Get());
+    parent_process_->child_process_logger().UpdateSandboxPolicy(policy);
     return RESULT_CODE_SUCCESS;
   }
 
@@ -69,38 +61,6 @@ class MojoSandboxSetupHooks : public SandboxSetupHooks {
 
 }  // namespace
 
-namespace internal {
-
-void PrintChildProcessLogs(const base::FilePath& log_path) {
-  if (log_path.empty()) {
-    LOG(ERROR) << "Child process log path is empty";
-    return;
-  }
-
-  if (!base::PathExists(log_path)) {
-    LOG(ERROR) << "Child process log file doesn't exist";
-    return;
-  }
-
-  // Collect the child process log file, and dump the contents, to help
-  // debugging failures.
-  std::string log_file_contents;
-  if (!base::ReadFileToString(log_path, &log_file_contents)) {
-    LOG(ERROR) << "Failed to read child process log file";
-    return;
-  }
-
-  std::vector<base::StringPiece> lines =
-      base::SplitStringPiece(log_file_contents, "\n", base::TRIM_WHITESPACE,
-                             base::SPLIT_WANT_NONEMPTY);
-  LOG(ERROR) << "Dumping child process logs";
-  for (const auto& line : lines) {
-    LOG(ERROR) << "Child process: " << line;
-  }
-}
-
-}  // namespace internal
-
 ParentProcess::ParentProcess(scoped_refptr<MojoTaskRunner> mojo_task_runner)
     : command_line_(base::GetMultiProcessTestChildBaseCommandLine()),
       mojo_task_runner_(mojo_task_runner) {}
@@ -158,36 +118,10 @@ bool ParentProcess::LaunchConnectedChildProcess(
     const std::string& child_main_function,
     base::TimeDelta timeout,
     int32_t* exit_code) {
-  // Adapted from
-  // https://cs.chromium.org/chromium/src/sandbox/win/src/handle_inheritance_test.cc
-  base::ScopedTempDir temp_dir;
-  if (!temp_dir.CreateUniqueTempDir()) {
-    PLOG(ERROR) << "Could not create temp dir for child stdout";
+  if (!child_process_logger_.Initialize())
     return false;
-  }
-
-  base::FilePath temp_file_name;
-  if (!CreateTemporaryFileInDir(temp_dir.GetPath(), &temp_file_name)) {
-    PLOG(ERROR) << "Could not create temp file for child stdout";
-    return false;
-  }
-
-  SECURITY_ATTRIBUTES attrs = {};
-  attrs.nLength = sizeof(attrs);
-  attrs.bInheritHandle = true;
-
-  base::win::ScopedHandle child_stdout_write_handle(
-      ::CreateFile(temp_file_name.value().c_str(), GENERIC_WRITE,
-                   FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE,
-                   &attrs, OPEN_EXISTING, 0, nullptr));
-  if (!child_stdout_write_handle.IsValid()) {
-    PLOG(ERROR) << "Could not open child stdout file";
-    return false;
-  }
-
-  if (!PrepareAndLaunchTestChildProcess(child_main_function,
-                                        std::move(child_stdout_write_handle))) {
-    internal::PrintChildProcessLogs(temp_file_name);
+  if (!PrepareAndLaunchTestChildProcess(child_main_function)) {
+    child_process_logger_.DumpLogs();
     return false;
   }
 
@@ -201,31 +135,22 @@ bool ParentProcess::LaunchConnectedChildProcess(
   DestroyImplOnIPCThread();
 
   if (!success || *exit_code != 0) {
-    internal::PrintChildProcessLogs(temp_file_name);
+    child_process_logger_.DumpLogs();
   }
 
   return success;
 }
 
 bool ParentProcess::PrepareAndLaunchTestChildProcess(
-    const std::string& child_main_function,
-    base::win::ScopedHandle child_stdout_write_handle) {
+    const std::string& child_main_function) {
   base::LaunchOptions launch_options;
   launch_options.handles_to_inherit = extra_handles_to_inherit_;
-  launch_options.handles_to_inherit.push_back(child_stdout_write_handle.Get());
-  launch_options.stdin_handle = INVALID_HANDLE_VALUE;
-  launch_options.stdout_handle = child_stdout_write_handle.Get();
-  launch_options.stderr_handle = child_stdout_write_handle.Get();
-
+  child_process_logger_.UpdateLaunchOptions(&launch_options);
   CreateMojoPipe(&command_line_, &launch_options.handles_to_inherit);
 
   base::Process child_process = base::SpawnMultiProcessTestChild(
       child_main_function, command_line_, launch_options);
 
-  // Now that it's been passed to the child process,
-  // |child_stdout_write_handle| can be closed in this process as it goes out
-  // of scope.
-
   ConnectMojoPipe(std::move(child_process));
   return true;
 }
@@ -257,9 +182,8 @@ SandboxedParentProcess::SandboxedParentProcess(
 SandboxedParentProcess::~SandboxedParentProcess() {}
 
 bool SandboxedParentProcess::PrepareAndLaunchTestChildProcess(
-    const std::string& child_main_function,
-    base::win::ScopedHandle child_stdout_write_handle) {
-  MojoSandboxSetupHooks hooks(this, std::move(child_stdout_write_handle));
+    const std::string& child_main_function) {
+  MojoSandboxSetupHooks hooks(this);
 
   // This switch usage is copied from SpawnMultiProcessTestChild.
   //
diff --git a/chrome/chrome_cleaner/ipc/ipc_test_util.h b/chrome/chrome_cleaner/ipc/ipc_test_util.h
index 1b2e5598ed52a..1526a42701353 100644
--- a/chrome/chrome_cleaner/ipc/ipc_test_util.h
+++ b/chrome/chrome_cleaner/ipc/ipc_test_util.h
@@ -14,9 +14,9 @@
 #include "base/process/launch.h"
 #include "base/process/process.h"
 #include "base/time/time.h"
-#include "base/win/scoped_handle.h"
 #include "chrome/chrome_cleaner/ipc/chrome_prompt_ipc.h"
 #include "chrome/chrome_cleaner/ipc/mojo_task_runner.h"
+#include "chrome/chrome_cleaner/test/child_process_logger.h"
 #include "mojo/public/cpp/platform/platform_channel.h"
 #include "mojo/public/cpp/system/invitation.h"
 #include "mojo/public/cpp/system/message_pipe.h"
@@ -58,6 +58,10 @@ class ParentProcess : public base::RefCountedThreadSafe<ParentProcess> {
     return extra_handles_to_inherit_;
   }
 
+  const ChildProcessLogger& child_process_logger() const {
+    return child_process_logger_;
+  }
+
  protected:
   friend base::RefCountedThreadSafe<ParentProcess>;
   virtual ~ParentProcess();
@@ -70,13 +74,13 @@ class ParentProcess : public base::RefCountedThreadSafe<ParentProcess> {
   // as in the sandbox. Subclasses should call CreateMojoPipe before the
   // subprocess is spawned and ConnectMojoPipe afterward.
   virtual bool PrepareAndLaunchTestChildProcess(
-      const std::string& child_main_function,
-      base::win::ScopedHandle child_stdout_write_handle);
+      const std::string& child_main_function);
 
   scoped_refptr<MojoTaskRunner> mojo_task_runner();
 
   base::CommandLine command_line_;
   base::HandlesToInheritVector extra_handles_to_inherit_;
+  ChildProcessLogger child_process_logger_;
 
  private:
   scoped_refptr<MojoTaskRunner> mojo_task_runner_;
@@ -96,8 +100,7 @@ class SandboxedParentProcess : public ParentProcess {
   ~SandboxedParentProcess() override;
 
   bool PrepareAndLaunchTestChildProcess(
-      const std::string& child_main_function,
-      base::win::ScopedHandle child_stdout_write_handle) override;
+      const std::string& child_main_function) override;
 };
 
 class ChildProcess : public base::RefCountedThreadSafe<ChildProcess> {
@@ -143,10 +146,6 @@ class ChromePromptIPCTestErrorHandler : public ChromePromptIPC::ErrorHandler {
   base::OnceClosure on_closed_after_done_;
 };
 
-namespace internal {
-void PrintChildProcessLogs(const base::FilePath& log_file);
-}  // namespace internal
-
 }  // namespace chrome_cleaner
 
 #endif  // CHROME_CHROME_CLEANER_IPC_IPC_TEST_UTIL_H_
diff --git a/chrome/chrome_cleaner/ipc/proto_chrome_prompt_ipc_unittest.cc b/chrome/chrome_cleaner/ipc/proto_chrome_prompt_ipc_unittest.cc
index f867df58f96ea..e3ce2ab6c27fe 100644
--- a/chrome/chrome_cleaner/ipc/proto_chrome_prompt_ipc_unittest.cc
+++ b/chrome/chrome_cleaner/ipc/proto_chrome_prompt_ipc_unittest.cc
@@ -5,7 +5,6 @@
 #include <windows.h>
 
 #include "base/command_line.h"
-#include "base/files/file_util.h"
 #include "base/process/process.h"
 #include "base/strings/strcat.h"
 #include "base/strings/string_number_conversions.h"
@@ -19,7 +18,7 @@
 #include "base/win/win_util.h"
 #include "chrome/chrome_cleaner/ipc/ipc_test_util.h"
 #include "chrome/chrome_cleaner/ipc/proto_chrome_prompt_ipc.h"
-#include "chrome/chrome_cleaner/logging/scoped_logging.h"
+#include "chrome/chrome_cleaner/test/child_process_logger.h"
 #include "components/chrome_cleaner/public/constants/constants.h"
 #include "components/chrome_cleaner/public/proto/chrome_prompt.pb.h"
 #include "components/chrome_cleaner/public/proto/chrome_prompt_for_tests.pb.h"
@@ -42,7 +41,6 @@ constexpr char kExpectedPromptResultSwitch[] = "expected-prompt-result";
 constexpr char kExpectedChromeDisconnectPointSwitch[] =
     "expected-parent-disconnected";
 
-constexpr base::char16 kLogSuffix[] = L"prompt-ipc-test";
 constexpr base::char16 kInvalidUTF16String[] = {0xDC00, 0xD800, 0xD800, 0xDFFF,
                                                 0xDFFF, 0xDBFF, 0};
 const base::FilePath kInvalidFilePath(kInvalidUTF16String);
@@ -421,8 +419,7 @@ class MockChrome {
 // Gtest to log.
 class ChildProcess {
  public:
-  ChildProcess()
-      : scopped_logging_(std::make_unique<ScopedLogging>(kLogSuffix)) {
+  ChildProcess() {
     mock_chrome_ = std::make_unique<MockChrome>(
         ExtractHandleFromCommandLine(chrome_cleaner::kChromeReadHandleSwitch),
         ExtractHandleFromCommandLine(chrome_cleaner::kChromeWriteHandleSwitch));
@@ -571,7 +568,6 @@ class ChildProcess {
 
  private:
   std::unique_ptr<MockChrome> mock_chrome_;
-  std::unique_ptr<ScopedLogging> scopped_logging_;
 
   ChromeDisconnectPoint expected_disconnect_point_ =
       ChromeDisconnectPoint::kUnspecified;
@@ -603,6 +599,9 @@ class ProtoChromePromptIPCTest
 class ParentProcess {
  public:
   bool Initialize() {
+    if (!child_process_logger_.Initialize())
+      return false;
+
     // Inject the flags related to the the config in the command line.
     test_config_.EnhanceCommandLine(&command_line_);
 
@@ -631,14 +630,13 @@ class ParentProcess {
   }
 
   void Run() {
-    // Delete the child process log file if existing.
-    const base::FilePath log_path = ScopedLogging::GetLogFilePath(kLogSuffix);
-    ASSERT_TRUE(base::DeleteFile(log_path, false))
-        << "Can't delete log file from previous run: " << log_path.value();
+    child_process_logger_.UpdateLaunchOptions(&launch_options_);
 
     // Pass the command to the child process and launch the child process.
     base::Process child_process = base::SpawnMultiProcessTestChild(
         "ProtoChromePromptIPCClientMain", command_line_, launch_options_);
+    if (!child_process.IsRunning())
+      child_process_logger_.DumpLogs();
     ASSERT_TRUE(child_process.IsRunning());
 
     // Close our references to the handles as they are now handled by the child
@@ -705,10 +703,8 @@ class ParentProcess {
 
     EXPECT_EQ(expected_exit_code, rv);
 
-    if (!success || rv != 0) {
-      internal::PrintChildProcessLogs(
-          ScopedLogging::GetLogFilePath(kLogSuffix));
-    }
+    if (!success || rv != 0)
+      child_process_logger_.DumpLogs();
   }
 
   TestConfig& GetTestConfig() { return test_config_; }
@@ -732,6 +728,8 @@ class ParentProcess {
   // Blocks until we receive the response from Chrome or an error occurs.
   base::RunLoop main_runloop_;
   bool error_occurred_ = false;
+
+  ChildProcessLogger child_process_logger_;
 };
 
 // This contains calls to the chrome_cleaner_ipc implementation.
diff --git a/chrome/chrome_cleaner/test/BUILD.gn b/chrome/chrome_cleaner/test/BUILD.gn
index 118454c2bdcd2..4b053fdcaf182 100644
--- a/chrome/chrome_cleaner/test/BUILD.gn
+++ b/chrome/chrome_cleaner/test/BUILD.gn
@@ -148,6 +148,8 @@ source_set("test_util") {
   testonly = true
 
   sources = [
+    "child_process_logger.cc",
+    "child_process_logger.h",
     "file_remover_test_util.cc",
     "file_remover_test_util.h",
     "reboot_deletion_helper.cc",
@@ -228,6 +230,7 @@ source_set("integration_test_sources") {
     "//chrome/chrome_cleaner/os:common_os",
     "//chrome/chrome_cleaner/pup_data:pup_data_base",
     "//chrome/chrome_cleaner/pup_data:test_uws",
+    "//chrome/chrome_cleaner/test:test_util",
     "//chrome/chrome_cleaner/zip_archiver:common",
     "//components/chrome_cleaner/public/constants",
     "//components/chrome_cleaner/test:test_name_helper",
diff --git a/chrome/chrome_cleaner/test/child_process_logger.cc b/chrome/chrome_cleaner/test/child_process_logger.cc
new file mode 100644
index 0000000000000..9f4836267aea6
--- /dev/null
+++ b/chrome/chrome_cleaner/test/child_process_logger.cc
@@ -0,0 +1,90 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/chrome_cleaner/test/child_process_logger.h"
+
+#include <vector>
+
+#include "base/files/file_util.h"
+#include "base/logging.h"
+#include "base/strings/string_piece.h"
+#include "base/strings/string_split.h"
+
+namespace chrome_cleaner {
+
+ChildProcessLogger::ChildProcessLogger() = default;
+
+ChildProcessLogger::~ChildProcessLogger() = default;
+
+bool ChildProcessLogger::Initialize() {
+  // Adapted from
+  // https://cs.chromium.org/chromium/src/sandbox/win/src/handle_inheritance_test.cc
+  if (!temp_dir_.CreateUniqueTempDir()) {
+    PLOG(ERROR) << "Could not create temp dir for child stdout";
+    return false;
+  }
+
+  if (!CreateTemporaryFileInDir(temp_dir_.GetPath(), &temp_file_name_)) {
+    PLOG(ERROR) << "Could not create temp file for child stdout";
+    return false;
+  }
+
+  SECURITY_ATTRIBUTES attrs = {};
+  attrs.nLength = sizeof(attrs);
+  attrs.bInheritHandle = true;
+
+  child_stdout_handle_.Set(
+      ::CreateFile(temp_file_name_.value().c_str(), GENERIC_WRITE,
+                   FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE,
+                   &attrs, OPEN_EXISTING, 0, nullptr));
+  if (!child_stdout_handle_.IsValid()) {
+    PLOG(ERROR) << "Could not open child stdout file";
+    return false;
+  }
+
+  return true;
+}
+
+void ChildProcessLogger::UpdateLaunchOptions(
+    base::LaunchOptions* options) const {
+  DCHECK(child_stdout_handle_.IsValid());
+  options->handles_to_inherit.push_back(child_stdout_handle_.Get());
+  options->stdin_handle = INVALID_HANDLE_VALUE;
+  options->stdout_handle = child_stdout_handle_.Get();
+  options->stderr_handle = child_stdout_handle_.Get();
+}
+
+void ChildProcessLogger::UpdateSandboxPolicy(
+    sandbox::TargetPolicy* policy) const {
+  DCHECK(child_stdout_handle_.IsValid());
+  policy->SetStdoutHandle(child_stdout_handle_.Get());
+  policy->SetStderrHandle(child_stdout_handle_.Get());
+}
+
+void ChildProcessLogger::DumpLogs() const {
+  DCHECK(!temp_file_name_.empty());
+
+  if (!base::PathExists(temp_file_name_)) {
+    LOG(ERROR) << "Child process log file doesn't exist";
+    return;
+  }
+
+  // Collect the child process log file, and dump the contents, to help
+  // debugging failures.
+  std::string log_file_contents;
+  if (!base::ReadFileToString(temp_file_name_, &log_file_contents)) {
+    LOG(ERROR) << "Failed to read child process log file";
+    return;
+  }
+
+  std::vector<base::StringPiece> lines =
+      base::SplitStringPiece(log_file_contents, "\n", base::TRIM_WHITESPACE,
+                             base::SPLIT_WANT_NONEMPTY);
+  LOG(ERROR) << "Dumping child process logs";
+  for (const auto& line : lines) {
+    LOG(ERROR) << "Child process: " << line;
+  }
+}
+
+}  // namespace chrome_cleaner
diff --git a/chrome/chrome_cleaner/test/child_process_logger.h b/chrome/chrome_cleaner/test/child_process_logger.h
new file mode 100644
index 0000000000000..215fa911d7899
--- /dev/null
+++ b/chrome/chrome_cleaner/test/child_process_logger.h
@@ -0,0 +1,62 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_CHROME_CLEANER_TEST_CHILD_PROCESS_LOGGER_H_
+#define CHROME_CHROME_CLEANER_TEST_CHILD_PROCESS_LOGGER_H_
+
+#include "base/files/scoped_temp_dir.h"
+#include "base/process/launch.h"
+#include "base/win/scoped_handle.h"
+#include "sandbox/win/src/sandbox_policy.h"
+
+namespace chrome_cleaner {
+
+// Redirects stdin and stdout of a child process to a temp file. Tests that
+// spawn children can add the contents of the temp file to the test output.
+//
+// Note that if the child process sets up ScopedLogging, ERROR and FATAL level
+// logs will still be captured by this, but other logs will start going to the
+// ScopedLogging log file. test_main.cc sets up ScopedLogging so usually this
+// class will capture:
+//
+// 1. All log lines from before the ScopedLogging constructor.
+// 2. ERROR and FATAL log lines from after that.
+// 3. stdout and stderr output that doesn't go through the logging system.
+// 4. Stack traces from any crashes.
+//
+// This should be all that's needed to diagnose errors in tests.
+class ChildProcessLogger {
+ public:
+  ChildProcessLogger();
+  ~ChildProcessLogger();
+
+  // Creates a temp file for child processes to log to. Logs an error and
+  // returns false on failure.
+  bool Initialize();
+
+  // Updates |options| to direct the child stdout and stderr to the temp file.
+  // For use with base::LaunchProcess and base::SpawnMultiProcessTestChild.
+  void UpdateLaunchOptions(base::LaunchOptions* options) const;
+
+  // Updates |policy| to direct the child stdout and stderr to the temp file.
+  // For use with sandbox::BrokerServices::SpawnTarget.
+  void UpdateSandboxPolicy(sandbox::TargetPolicy* policy) const;
+
+  // Writes every line in the temp file using LOG(ERROR) so that all lines are
+  // captured in the test suite output. The class-level comment above describes
+  // which log lines from the child will be captured.
+  void DumpLogs() const;
+
+ private:
+  ChildProcessLogger(const ChildProcessLogger& other) = delete;
+  ChildProcessLogger& operator=(const ChildProcessLogger& other) = delete;
+
+  base::ScopedTempDir temp_dir_;
+  base::FilePath temp_file_name_;
+  base::win::ScopedHandle child_stdout_handle_;
+};
+
+}  // namespace chrome_cleaner
+
+#endif  // CHROME_CHROME_CLEANER_TEST_CHILD_PROCESS_LOGGER_H_
diff --git a/chrome/chrome_cleaner/test/cleaner_test.cc b/chrome/chrome_cleaner/test/cleaner_test.cc
index d6df17e3516f1..f778103bfdad3 100644
--- a/chrome/chrome_cleaner/test/cleaner_test.cc
+++ b/chrome/chrome_cleaner/test/cleaner_test.cc
@@ -24,6 +24,7 @@
 #include "chrome/chrome_cleaner/os/pre_fetched_paths.h"
 #include "chrome/chrome_cleaner/pup_data/pup_data.h"
 #include "chrome/chrome_cleaner/pup_data/test_uws.h"
+#include "chrome/chrome_cleaner/test/child_process_logger.h"
 #include "chrome/chrome_cleaner/test/test_util.h"
 #include "chrome/chrome_cleaner/zip_archiver/sandboxed_zip_archiver.h"
 #include "components/chrome_cleaner/public/constants/constants.h"
@@ -311,8 +312,14 @@ class CleanerTest
 
   void ExpectExitCode(const base::CommandLine& command_line,
                       int expected_exit_code) {
-    base::Process process(
-        base::LaunchProcess(command_line, base::LaunchOptions()));
+    chrome_cleaner::ChildProcessLogger logger;
+    ASSERT_TRUE(logger.Initialize());
+
+    base::LaunchOptions options;
+    logger.UpdateLaunchOptions(&options);
+    base::Process process(base::LaunchProcess(command_line, options));
+    if (!process.IsValid())
+      logger.DumpLogs();
     ASSERT_TRUE(process.IsValid());
 
     int exit_code = -1;
@@ -320,7 +327,8 @@ class CleanerTest
         base::TimeDelta::FromMinutes(10), &exit_code);
     EXPECT_TRUE(exited_within_timeout);
     EXPECT_EQ(expected_exit_code, exit_code);
-
+    if (!exited_within_timeout || expected_exit_code != exit_code)
+      logger.DumpLogs();
     if (!exited_within_timeout)
       process.Terminate(/*exit_code=*/-1, /*wait=*/false);
   }
diff --git a/chrome/chrome_cleaner/test/secure_dll_loading_test.cc b/chrome/chrome_cleaner/test/secure_dll_loading_test.cc
index fe10c44346b5e..92e2db19fde6c 100644
--- a/chrome/chrome_cleaner/test/secure_dll_loading_test.cc
+++ b/chrome/chrome_cleaner/test/secure_dll_loading_test.cc
@@ -8,22 +8,17 @@
 
 #include <memory>
 #include <set>
-#include <string>
 #include <vector>
 
 #include "base/base_paths.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
-#include "base/files/file_util.h"
-#include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "base/process/launch.h"
 #include "base/process/process.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
-#include "base/strings/string_piece.h"
-#include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/test/test_timeouts.h"
@@ -32,54 +27,16 @@
 #include "chrome/chrome_cleaner/constants/chrome_cleaner_switches.h"
 #include "chrome/chrome_cleaner/os/inheritable_event.h"
 #include "chrome/chrome_cleaner/os/process.h"
+#include "chrome/chrome_cleaner/test/child_process_logger.h"
 #include "chrome/chrome_cleaner/test/test_util.h"
 #include "components/chrome_cleaner/public/constants/constants.h"
 #include "components/chrome_cleaner/test/test_name_helper.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace {
-
-void PrintChildProcessLogs(const base::FilePath& log_dir,
-                           base::StringPiece16 file_name) {
-  base::string16 base_name;
-  if (file_name == L"software_reporter_tool") {
-    base_name = L"software_reporter_tool";
-  } else if (file_name == L"chrome_cleanup_tool") {
-    base_name = L"chrome_cleanup";
-  } else {
-    LOG(ERROR) << "Unknown file name " << file_name.data();
-    return;
-  }
-
-  base::FilePath log_path = log_dir.Append(base_name).AddExtension(L"log");
-
-  if (!base::PathExists(log_path)) {
-    LOG(ERROR) << "Child process log file doesn't exist";
-    return;
-  }
-
-  // Collect the child process log file, and dump the contents, to help
-  // debugging failures.
-  std::string log_file_contents;
-  if (!base::ReadFileToString(log_path, &log_file_contents)) {
-    LOG(ERROR) << "Failed to read child process log file";
-    return;
-  }
-
-  std::vector<base::StringPiece> lines =
-      base::SplitStringPiece(log_file_contents, "\n", base::TRIM_WHITESPACE,
-                             base::SPLIT_WANT_NONEMPTY);
-  LOG(ERROR) << "Dumping child process logs";
-  for (const auto& line : lines) {
-    LOG(ERROR) << "Child process: " << line;
-  }
-}
-
-}  // namespace
-
 class SecureDLLLoadingTest : public testing::TestWithParam<base::string16> {
  protected:
   void SetUp() override {
+    ASSERT_TRUE(child_process_logger_.Initialize());
     base::FilePath out_dir;
     ASSERT_TRUE(base::PathService::Get(base::DIR_EXE, &out_dir));
     exe_path_ = out_dir.Append(GetParam() + L".exe");
@@ -104,8 +61,6 @@ class SecureDLLLoadingTest : public testing::TestWithParam<base::string16> {
         base::NumberToString16(
             base::win::HandleToUint32(init_done_notifier->handle())));
     command_line.AppendSwitch(chrome_cleaner::kLoadEmptyDLLSwitch);
-    command_line.AppendSwitchPath(chrome_cleaner::kTestLoggingPathSwitch,
-                                  log_dir.GetPath());
 
 #if !BUILDFLAG(IS_OFFICIAL_CHROME_CLEANER_BUILD)
     if (disable_secure_dll_loading)
@@ -121,7 +76,12 @@ class SecureDLLLoadingTest : public testing::TestWithParam<base::string16> {
 
     base::LaunchOptions options;
     options.handles_to_inherit.push_back(init_done_notifier->handle());
+    child_process_logger_.UpdateLaunchOptions(&options);
     base::Process process = base::LaunchProcess(command_line, options);
+    if (!process.IsValid()) {
+      child_process_logger_.DumpLogs();
+      return process;
+    }
 
     // Make sure the process has finished its initialization (including loading
     // DLLs). Also check the process handle in case it exits with an error.
@@ -136,7 +96,7 @@ class SecureDLLLoadingTest : public testing::TestWithParam<base::string16> {
       PLOG_IF(ERROR, !::GetExitCodeProcess(process.Handle(), &exit_code));
       ADD_FAILURE() << "Process exited with " << exit_code
                     << " before signalling init_done_notifier";
-      PrintChildProcessLogs(log_dir.GetPath(), GetParam());
+      child_process_logger_.DumpLogs();
     } else {
       EXPECT_EQ(wait_result, WAIT_OBJECT_0);
     }
@@ -157,6 +117,7 @@ class SecureDLLLoadingTest : public testing::TestWithParam<base::string16> {
   }
 
  private:
+  chrome_cleaner::ChildProcessLogger child_process_logger_;
   base::FilePath exe_path_;
   base::FilePath empty_dll_path_;
 };