Simplify initialization of utility thread.

Utility thread is a thread for utilities that make use of Blink.
Currently, the WebThread object for that thread is defined as
WebThreadImplForUtilityThread, but we can remove it if we initialize
Blink with blink::CreateMainThreadAndInitialize(), because the
utility thread does not require multi-thread nor other complex
functionalities.

UtilityBlinkPlatformImpl inherits from BlinkPlatformImpl, which is
a base class for blink::Platform defined in content/. This patch
makes it directly inherit from blink::Platform, since the utility
thread does not require functions defined in BlinkPlatformImpl --
BlinkPlatformImpl's functions are basically for full-fledged browser,
and we don't need them in the utility thread.

Bug: 826203
Change-Id: I57af86931af176ef5d1bd08d0f0ceb5e60d9d65b
Reviewed-on: https://chromium-review.googlesource.com/1175746
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584030}

content/utility/BUILD.gn

@@ -17,8 +17,6 @@ jumbo_source_set("utility") {
   sources = [
     "in_process_utility_thread.cc",
     "in_process_utility_thread.h",
-    "utility_blink_platform_impl.cc",
-    "utility_blink_platform_impl.h",
     "utility_blink_platform_with_sandbox_support_impl.cc",
     "utility_blink_platform_with_sandbox_support_impl.h",
     "utility_main.cc",

content/utility/utility_blink_platform_impl.cc

-// Copyright 2015 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 "content/utility/utility_blink_platform_impl.h"
-
-#include "third_party/blink/public/platform/scheduler/child/webthread_base.h"
-
-namespace content {
-
-UtilityBlinkPlatformImpl::UtilityBlinkPlatformImpl()
-    : main_thread_(blink::scheduler::WebThreadBase::InitializeUtilityThread()) {
-}
-
-UtilityBlinkPlatformImpl::~UtilityBlinkPlatformImpl() {
-}
-
-blink::WebThread* UtilityBlinkPlatformImpl::CurrentThread() {
-  if (main_thread_->IsCurrentThread())
-    return main_thread_.get();
-  return BlinkPlatformImpl::CurrentThread();
-}
-
-}  // namespace content

content/utility/utility_blink_platform_impl.h

-// Copyright 2015 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 CONTENT_UTILITY_UTILITY_BLINK_PLATFORM_IMPL_H_
-#define CONTENT_UTILITY_UTILITY_BLINK_PLATFORM_IMPL_H_
-
-#include <memory>
-
-#include "base/macros.h"
-#include "content/child/blink_platform_impl.h"
-
-namespace blink {
-namespace scheduler {
-class WebThreadBase;
-}
-}
-
-namespace content {
-
-class UtilityBlinkPlatformImpl : public BlinkPlatformImpl {
- public:
-  UtilityBlinkPlatformImpl();
-  ~UtilityBlinkPlatformImpl() override;
-
-  // BlinkPlatformImpl implementation.
-  blink::WebThread* CurrentThread() override;
-
- private:
-  std::unique_ptr<blink::scheduler::WebThreadBase> main_thread_;
-
-  DISALLOW_COPY_AND_ASSIGN(UtilityBlinkPlatformImpl);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_UTILITY_UTILITY_BLINK_PLATFORM_IMPL_H_

content/utility/utility_blink_platform_with_sandbox_support_impl.h

@@ -9,7 +9,7 @@
 
 #include "base/macros.h"
 #include "build/build_config.h"
-#include "content/utility/utility_blink_platform_impl.h"
+#include "third_party/blink/public/platform/platform.h"
 
 #if defined(OS_POSIX) && !defined(OS_ANDROID)
 #include "components/services/font/public/cpp/font_loader.h"  // nogncheck
@@ -28,8 +28,7 @@ namespace content {
 
 // This class extends from UtilityBlinkPlatformImpl with added blink web
 // sandbox support.
-class UtilityBlinkPlatformWithSandboxSupportImpl
-    : public UtilityBlinkPlatformImpl {
+class UtilityBlinkPlatformWithSandboxSupportImpl : public blink::Platform {
  public:
   UtilityBlinkPlatformWithSandboxSupportImpl() = delete;
   explicit UtilityBlinkPlatformWithSandboxSupportImpl(

content/utility/utility_thread_impl.cc

@@ -8,12 +8,10 @@
 
 #include "base/command_line.h"
 #include "build/build_config.h"
-#include "content/child/blink_platform_impl.h"
 #include "content/child/child_process.h"
 #include "content/public/common/service_manager_connection.h"
 #include "content/public/common/simple_connection_filter.h"
 #include "content/public/utility/content_utility_client.h"
-#include "content/utility/utility_blink_platform_impl.h"
 #include "content/utility/utility_blink_platform_with_sandbox_support_impl.h"
 #include "content/utility/utility_service_factory.h"
 #include "ipc/ipc_sync_channel.h"
@@ -120,9 +118,8 @@ void UtilityThreadImpl::EnsureBlinkInitializedInternal(bool sandbox_support) {
       sandbox_support
           ? std::make_unique<UtilityBlinkPlatformWithSandboxSupportImpl>(
                 GetConnector())
-          : std::make_unique<UtilityBlinkPlatformImpl>();
-  blink::Platform::Initialize(blink_platform_impl_.get(),
-                              blink_platform_impl_->CurrentThread());
+          : std::make_unique<blink::Platform>();
+  blink::Platform::CreateMainThreadAndInitialize(blink_platform_impl_.get());
 }
 
 void UtilityThreadImpl::Init() {

content/utility/utility_thread_impl.h

@@ -14,9 +14,9 @@
 #include "content/public/utility/utility_thread.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "services/service_manager/public/mojom/service_factory.mojom.h"
+#include "third_party/blink/public/platform/platform.h"
 
 namespace content {
-class UtilityBlinkPlatformImpl;
 class UtilityServiceFactory;
 
 namespace mojom {
@@ -64,7 +64,7 @@ class UtilityThreadImpl : public UtilityThread,
       service_manager::mojom::ServiceFactoryRequest request);
 
   // blink::Platform implementation if needed.
-  std::unique_ptr<UtilityBlinkPlatformImpl> blink_platform_impl_;
+  std::unique_ptr<blink::Platform> blink_platform_impl_;
 
   // service_manager::mojom::ServiceFactory for service_manager::Service
   // hosting.

services/data_decoder/image_decoder_impl_unittest.cc

@@ -13,7 +13,6 @@
 #include "services/data_decoder/image_decoder_impl.h"
 #include "services/service_manager/public/cpp/binder_registry.h"
 #include "testing/gtest/include/gtest/gtest.h"
-#include "third_party/blink/public/platform/scheduler/child/webthread_base.h"
 #include "third_party/blink/public/web/blink.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/codec/jpeg_codec.h"
@@ -78,25 +77,19 @@ class Request {
 // image decoding call.
 class BlinkInitializer : public blink::Platform {
  public:
-  BlinkInitializer()
-      : main_thread_(
-            blink::scheduler::WebThreadBase::InitializeUtilityThread()) {
+  BlinkInitializer() {
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
     gin::V8Initializer::LoadV8Snapshot(kSnapshotType);
     gin::V8Initializer::LoadV8Natives();
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 
     service_manager::BinderRegistry empty_registry;
-    blink::Initialize(this, &empty_registry, CurrentThread());
+    blink::CreateMainThreadAndInitialize(this, &empty_registry);
   }
 
   ~BlinkInitializer() override {}
 
-  blink::WebThread* CurrentThread() override { return main_thread_.get(); }
-
  private:
-  std::unique_ptr<blink::scheduler::WebThreadBase> main_thread_;
-
   DISALLOW_COPY_AND_ASSIGN(BlinkInitializer);
 };
 

third_party/blink/public/platform/platform.h

@@ -160,6 +160,9 @@ class BLINK_PLATFORM_EXPORT Platform {
   // You should not pass in a Platform object that is not fully instantiated.
   static void SetCurrentPlatformForTesting(Platform*);
 
+  Platform();
+  virtual ~Platform();
+
   // May return null.
   virtual WebCookieJar* CookieJar() { return nullptr; }
 
@@ -702,9 +705,6 @@ class BLINK_PLATFORM_EXPORT Platform {
   virtual bool IsTakingV8ContextSnapshot() { return false; }
 
  protected:
-  Platform();
-  virtual ~Platform();
-
   WebThread* main_thread_;
 
  private:

third_party/blink/public/platform/scheduler/child/webthread_base.h

@@ -33,8 +33,6 @@ class BLINK_PLATFORM_EXPORT WebThreadBase : public WebThread {
       const WebThreadCreationParams& params);
   static std::unique_ptr<WebThreadBase> CreateCompositorThread(
       const WebThreadCreationParams& params);
-  // Must be called on utility thread.
-  static std::unique_ptr<WebThreadBase> InitializeUtilityThread();
 
   // WebThread implementation.
   bool IsCurrentThread() const override;

third_party/blink/renderer/platform/scheduler/BUILD.gn

@@ -110,8 +110,6 @@ blink_platform_sources("scheduler") {
     "util/thread_type.h",
     "util/tracing_helper.cc",
     "util/tracing_helper.h",
-    "utility/webthread_impl_for_utility_thread.cc",
-    "utility/webthread_impl_for_utility_thread.h",
     "worker/compositor_metrics_helper.cc",
     "worker/compositor_metrics_helper.h",
     "worker/compositor_thread_scheduler.cc",

third_party/blink/renderer/platform/scheduler/child/webthread_base.cc

@@ -16,7 +16,6 @@
 #include "base/pending_task.h"
 #include "base/threading/platform_thread.h"
 #include "third_party/blink/renderer/platform/scheduler/child/webthread_impl_for_worker_scheduler.h"
-#include "third_party/blink/renderer/platform/scheduler/utility/webthread_impl_for_utility_thread.h"
 #include "third_party/blink/renderer/platform/scheduler/worker/compositor_thread_scheduler.h"
 
 namespace blink {
@@ -124,9 +123,5 @@ std::unique_ptr<WebThreadBase> WebThreadBase::CreateCompositorThread(
   return std::make_unique<WebThreadForCompositor>(params);
 }
 
-std::unique_ptr<WebThreadBase> WebThreadBase::InitializeUtilityThread() {
-  return std::make_unique<WebThreadImplForUtilityThread>();
-}
-
 }  // namespace scheduler
 }  // namespace blink

third_party/blink/renderer/platform/scheduler/utility/webthread_impl_for_utility_thread.cc

-// Copyright 2015 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 "third_party/blink/renderer/platform/scheduler/utility/webthread_impl_for_utility_thread.h"
-
-#include "base/threading/thread_task_runner_handle.h"
-
-namespace blink {
-namespace scheduler {
-
-WebThreadImplForUtilityThread::WebThreadImplForUtilityThread()
-    : task_runner_(base::ThreadTaskRunnerHandle::Get()),
-      thread_id_(base::PlatformThread::CurrentId()) {}
-
-WebThreadImplForUtilityThread::~WebThreadImplForUtilityThread() = default;
-
-blink::ThreadScheduler* WebThreadImplForUtilityThread::Scheduler() const {
-  return nullptr;
-}
-
-blink::PlatformThreadId WebThreadImplForUtilityThread::ThreadId() const {
-  return thread_id_;
-}
-
-scoped_refptr<base::SingleThreadTaskRunner>
-WebThreadImplForUtilityThread::GetTaskRunner() const {
-  return task_runner_;
-}
-
-void WebThreadImplForUtilityThread::Init() {}
-
-}  // namespace scheduler
-}  // namespace blink

third_party/blink/renderer/platform/scheduler/utility/webthread_impl_for_utility_thread.h

-// Copyright 2015 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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCHEDULER_UTILITY_WEBTHREAD_IMPL_FOR_UTILITY_THREAD_H_
-#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCHEDULER_UTILITY_WEBTHREAD_IMPL_FOR_UTILITY_THREAD_H_
-
-#include "base/macros.h"
-#include "base/memory/scoped_refptr.h"
-#include "base/single_thread_task_runner.h"
-#include "third_party/blink/public/platform/scheduler/child/webthread_base.h"
-#include "third_party/blink/renderer/platform/platform_export.h"
-
-namespace blink {
-namespace scheduler {
-
-class PLATFORM_EXPORT WebThreadImplForUtilityThread
-    : public scheduler::WebThreadBase {
- public:
-  WebThreadImplForUtilityThread();
-  ~WebThreadImplForUtilityThread() override;
-
-  // WebThread implementation.
-  ThreadScheduler* Scheduler() const override;
-  PlatformThreadId ThreadId() const override;
-  scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() const override;
-
-  // WebThreadBase implementation.
-  void Init() override;
-
- private:
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
-  PlatformThreadId thread_id_;
-
-  DISALLOW_COPY_AND_ASSIGN(WebThreadImplForUtilityThread);
-};
-
-}  // namespace scheduler
-}  // namespace blink
-
-#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCHEDULER_UTILITY_WEBTHREAD_IMPL_FOR_UTILITY_THREAD_H_