Move content::ScopedWebCallbacks to blink platform.

The content::ScopedWebCallbacks class is a helper for blink::WebCallbacks
and does not do anything strictly related to //content.
Moving it to //third_party/blink/public/platform makes it possible
to use it in all blink platform consumer, also the ones outside of //content,
such as //media/blink.
One example is //media/blink/webmediacapabilitiesclient_impl.cc which before
had to use specialized local copy of it.

This also adds two modifications to ScopedWebCallbacks:
* Make make_scoped_web_callbacks take a unique_ptr to WebCallbacks,
  instead of raw pointer that gets silently WrapUnique'ed inside,
  to make ownership passing more explicit,
* Modernize it to operate on OnceCallback, instead of Callback,
* Use default move constructor and move assignment.

Bug: 847211
Change-Id: I3d9b8a660dbfd66cf8721331777f36ea42c04bc8
Reviewed-on: https://chromium-review.googlesource.com/1104356
Commit-Queue: Chrome Cunningham <chcunningham@chromium.org>
Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568572}

content/child/BUILD.gn

@@ -67,7 +67,6 @@ target(link_target_type, "child") {
     "runtime_features.h",
     "scoped_child_process_reference.cc",
     "scoped_child_process_reference.h",
-    "scoped_web_callbacks.h",
     "service_factory.cc",
     "service_factory.h",
     "thread_safe_sender.cc",

content/renderer/image_capture/image_capture_frame_grabber.cc

@@ -115,7 +115,7 @@ ImageCaptureFrameGrabber::~ImageCaptureFrameGrabber() {
 
 void ImageCaptureFrameGrabber::GrabFrame(
     blink::WebMediaStreamTrack* track,
-    WebImageCaptureGrabFrameCallbacks* callbacks) {
+    std::unique_ptr<blink::WebImageCaptureGrabFrameCallbacks> callbacks) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!!callbacks);
 
@@ -128,8 +128,8 @@ void ImageCaptureFrameGrabber::GrabFrame(
     return;
   }
 
-  ScopedWebCallbacks<WebImageCaptureGrabFrameCallbacks> scoped_callbacks =
-      make_scoped_web_callbacks(callbacks, base::Bind(&OnError));
+  auto scoped_callbacks = blink::MakeScopedWebCallbacks(
+      std::move(callbacks), base::BindOnce(&OnError));
 
   // A SingleShotFrameHandler is bound and given to the Track to guarantee that
   // only one VideoFrame is converted and delivered to OnSkImage(), otherwise
@@ -149,7 +149,8 @@ void ImageCaptureFrameGrabber::GrabFrame(
 }
 
 void ImageCaptureFrameGrabber::OnSkImage(
-    ScopedWebCallbacks<blink::WebImageCaptureGrabFrameCallbacks> callbacks,
+    blink::ScopedWebCallbacks<blink::WebImageCaptureGrabFrameCallbacks>
+        callbacks,
     sk_sp<SkImage> image) {
   DCHECK(thread_checker_.CalledOnValidThread());
 

content/renderer/image_capture/image_capture_frame_grabber.h

@@ -5,13 +5,15 @@
 #ifndef CONTENT_RENDERER_IMAGE_CAPTURE_IMAGE_CAPTURE_FRAME_GRABBER_H_
 #define CONTENT_RENDERER_IMAGE_CAPTURE_IMAGE_CAPTURE_FRAME_GRABBER_H_
 
+#include <memory>
+
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
-#include "content/child/scoped_web_callbacks.h"
 #include "content/common/content_export.h"
 #include "content/public/renderer/media_stream_video_sink.h"
+#include "third_party/blink/public/platform/scoped_web_callbacks.h"
 #include "third_party/blink/public/platform/web_image_capture_frame_grabber.h"
 
 namespace blink {
@@ -36,14 +38,15 @@ class CONTENT_EXPORT ImageCaptureFrameGrabber final
 
   // blink::WebImageCaptureFrameGrabber implementation.
   void GrabFrame(blink::WebMediaStreamTrack* track,
-                 blink::WebImageCaptureGrabFrameCallbacks* callbacks) override;
+                 std::unique_ptr<blink::WebImageCaptureGrabFrameCallbacks>
+                     callbacks) override;
 
  private:
   // Internal class to receive, convert and forward one frame.
   class SingleShotFrameHandler;
 
-  void OnSkImage(
-      ScopedWebCallbacks<blink::WebImageCaptureGrabFrameCallbacks> callbacks,
+  void OnSkImage(blink::ScopedWebCallbacks<
+                     blink::WebImageCaptureGrabFrameCallbacks> callbacks,
                  sk_sp<SkImage> image);
 
   // Flag to indicate that there is a frame grabbing in progress.

content/renderer/media_recorder/media_recorder_handler.cc

@@ -13,7 +13,6 @@
 #include "base/strings/string_tokenizer.h"
 #include "base/strings/string_util.h"
 #include "base/sys_info.h"
-#include "content/child/scoped_web_callbacks.h"
 #include "content/renderer/media/stream/media_stream_audio_track.h"
 #include "content/renderer/media/stream/media_stream_track.h"
 #include "content/renderer/media/webrtc/webrtc_uma_histograms.h"
@@ -27,6 +26,7 @@
 #include "media/base/video_frame.h"
 #include "media/muxers/webm_muxer.h"
 #include "third_party/blink/public/platform/modules/media_capabilities/web_media_configuration.h"
+#include "third_party/blink/public/platform/scoped_web_callbacks.h"
 #include "third_party/blink/public/platform/web_media_recorder_handler_client.h"
 #include "third_party/blink/public/platform/web_media_stream_source.h"
 #include "third_party/blink/public/platform/web_string.h"
@@ -350,9 +350,8 @@ void MediaRecorderHandler::EncodingInfo(
   DCHECK(configuration.video_configuration ||
          configuration.audio_configuration);
 
-  ScopedWebCallbacks<WebMediaCapabilitiesQueryCallbacks> scoped_callbacks =
-      make_scoped_web_callbacks(callbacks.release(),
-                                base::Bind(&OnEncodingInfoError));
+  auto scoped_callbacks = blink::MakeScopedWebCallbacks(
+      std::move(callbacks), base::BindOnce(&OnEncodingInfoError));
 
   std::unique_ptr<blink::WebMediaCapabilitiesInfo> info(
       new blink::WebMediaCapabilitiesInfo());

media/blink/webmediacapabilitiesclient_impl.cc

@@ -22,6 +22,7 @@
 #include "third_party/blink/public/platform/modules/media_capabilities/web_media_configuration.h"
 #include "third_party/blink/public/platform/modules/media_capabilities/web_video_configuration.h"
 #include "third_party/blink/public/platform/platform.h"
+#include "third_party/blink/public/platform/scoped_web_callbacks.h"
 
 namespace media {
 
@@ -141,30 +142,21 @@ WebMediaCapabilitiesClientImpl::WebMediaCapabilitiesClientImpl() = default;
 WebMediaCapabilitiesClientImpl::~WebMediaCapabilitiesClientImpl() = default;
 
 namespace {
-// This structs wraps WebMediaCapabilitiesQueryCallbacks and makes sure
-// they are called even when the mojo response is not received
-// (connection error) as there is a pending promise waiting for the callback.
-// See https://crbug.com/847211
-struct CallbacksHolder {
-  std::unique_ptr<blink::WebMediaCapabilitiesQueryCallbacks> callbacks;
-
-  CallbacksHolder(CallbacksHolder&&) = default;
-  ~CallbacksHolder() {
-    if (callbacks) {
-      callbacks->OnError();
-    }
-  }
-};
-
 void VideoPerfInfoCallback(
-    CallbacksHolder callbacks_holder,
+    blink::ScopedWebCallbacks<blink::WebMediaCapabilitiesQueryCallbacks>
+        scoped_callbacks,
     std::unique_ptr<blink::WebMediaCapabilitiesInfo> info,
     bool is_smooth,
     bool is_power_efficient) {
   DCHECK(info->supported);
   info->smooth = is_smooth;
   info->power_efficient = is_power_efficient;
-  std::move(callbacks_holder.callbacks)->OnSuccess(std::move(info));
+  scoped_callbacks.PassCallbacks()->OnSuccess(std::move(info));
+}
+
+void OnGetPerfInfoError(
+    std::unique_ptr<blink::WebMediaCapabilitiesQueryCallbacks> callbacks) {
+  callbacks->OnError();
 }
 }  // namespace
 
@@ -226,8 +218,11 @@ void WebMediaCapabilitiesClientImpl::DecodingInfo(
 
   decode_history_ptr_->GetPerfInfo(
       std::move(features),
-      base::BindOnce(&VideoPerfInfoCallback,
-                     CallbacksHolder{std::move(callbacks)}, std::move(info)));
+      base::BindOnce(
+          &VideoPerfInfoCallback,
+          blink::MakeScopedWebCallbacks(std::move(callbacks),
+                                        base::BindOnce(&OnGetPerfInfoError)),
+          std::move(info)));
 }
 
 void WebMediaCapabilitiesClientImpl::BindVideoDecodePerfHistoryForTests(

third_party/blink/public/BUILD.gn

@@ -195,6 +195,7 @@ source_set("blink_headers") {
     "platform/scheduler/web_main_thread_scheduler.h",
     "platform/scheduler/web_render_widget_scheduling_state.h",
     "platform/scheduler/web_thread_scheduler.h",
+    "platform/scoped_web_callbacks.h",
     "platform/shape_properties.h",
     "platform/task_type.h",
     "platform/url_conversion.h",

content/child/scoped_web_callbacks.h → third_party/blink/public/platform/scoped_web_callbacks.h

-// Copyright 2015 The Chromium Authors. All rights reserved.
+// Copyright 2018 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_CHILD_SCOPED_WEB_CALLBACKS_H_
-#define CONTENT_CHILD_SCOPED_WEB_CALLBACKS_H_
+#ifndef THIRD_PARTY_BLINK_PUBLIC_PLATFORM_SCOPED_WEB_CALLBACKS_H_
+#define THIRD_PARTY_BLINK_PUBLIC_PLATFORM_SCOPED_WEB_CALLBACKS_H_
 
 #include <memory>
 #include <utility>
 
 #include "base/callback.h"
-#include "base/macros.h"
-#include "base/memory/ptr_util.h"
 #include "third_party/blink/public/platform/web_callbacks.h"
 
+namespace blink {
+
 // A ScopedWebCallbacks is a move-only scoper which helps manage the lifetime of
 // a blink::WebCallbacks object. This is particularly useful when you're
 // simultaneously dealing with the following two conditions:
@@ -48,14 +48,14 @@
 //   }
 //
 //   // Blink client implementation
-//   void FooClientImpl::doMagic(FooCallbacks* callbacks) {
+//   void FooClientImpl::doMagic(std::unique_ptr<FooCallbacks> callbacks) {
 //     auto scoped_callbacks = make_scoped_web_callbacks(
-//         callbacks, base::Bind(&OnCallbacksDropped));
+//         std::move(callbacks), base::BindOnce(&OnCallbacksDropped));
 //
 //     // Call to some lower-level service which may never run the callback we
 //     // give it.
-//     foo_service_->DoMagic(base::Bind(&RespondWithSuccess,
-//                                      base::Passed(&scoped_callbacks)));
+//     foo_service_->DoMagic(base::BindOnce(&RespondWithSuccess,
+//                                          std::move(scoped_callbacks)));
 //   }
 //
 // If the bound RespondWithSuccess callback actually runs, PassCallbacks() will
@@ -69,44 +69,43 @@ template <typename CallbacksType>
 class ScopedWebCallbacks {
  public:
   using DestructionCallback =
-      base::Callback<void(std::unique_ptr<CallbacksType> callbacks)>;
+      base::OnceCallback<void(std::unique_ptr<CallbacksType> callbacks)>;
 
   ScopedWebCallbacks(std::unique_ptr<CallbacksType> callbacks,
-                     const DestructionCallback& destruction_callback)
+                     DestructionCallback destruction_callback)
       : callbacks_(std::move(callbacks)),
-        destruction_callback_(destruction_callback) {}
+        destruction_callback_(std::move(destruction_callback)) {}
 
   ~ScopedWebCallbacks() {
-    if (callbacks_)
-      destruction_callback_.Run(std::move(callbacks_));
+    if (destruction_callback_)
+      std::move(destruction_callback_).Run(std::move(callbacks_));
   }
 
-  ScopedWebCallbacks(ScopedWebCallbacks&& other) { *this = std::move(other); }
+  ScopedWebCallbacks(ScopedWebCallbacks&& other) = default;
+  ScopedWebCallbacks(const ScopedWebCallbacks& other) = delete;
 
-  ScopedWebCallbacks& operator=(ScopedWebCallbacks&& other) {
-    callbacks_ = std::move(other.callbacks_);
-    destruction_callback_ = other.destruction_callback_;
-    return *this;
-  }
+  ScopedWebCallbacks& operator=(ScopedWebCallbacks&& other) = default;
+  ScopedWebCallbacks& operator=(const ScopedWebCallbacks& other) = delete;
 
   std::unique_ptr<CallbacksType> PassCallbacks() {
+    destruction_callback_ = DestructionCallback();
     return std::move(callbacks_);
   }
 
  private:
   std::unique_ptr<CallbacksType> callbacks_;
   DestructionCallback destruction_callback_;
-
-  DISALLOW_COPY_AND_ASSIGN(ScopedWebCallbacks);
 };
 
 template <typename CallbacksType>
-ScopedWebCallbacks<CallbacksType> make_scoped_web_callbacks(
-    CallbacksType* callbacks,
-    const typename ScopedWebCallbacks<CallbacksType>::DestructionCallback&
+ScopedWebCallbacks<CallbacksType> MakeScopedWebCallbacks(
+    std::unique_ptr<CallbacksType> callbacks,
+    typename ScopedWebCallbacks<CallbacksType>::DestructionCallback
         destruction_callback) {
-  return ScopedWebCallbacks<CallbacksType>(base::WrapUnique(callbacks),
-                                           destruction_callback);
+  return ScopedWebCallbacks<CallbacksType>(std::move(callbacks),
+                                           std::move(destruction_callback));
 }
 
-#endif  // CONTENT_CHILD_SCOPED_WEB_CALLBACKS_H_
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_PUBLIC_PLATFORM_SCOPED_WEB_CALLBACKS_H_

third_party/blink/public/platform/web_image_capture_frame_grabber.h

@@ -5,6 +5,8 @@
 #ifndef THIRD_PARTY_BLINK_PUBLIC_PLATFORM_WEB_IMAGE_CAPTURE_FRAME_GRABBER_H_
 #define THIRD_PARTY_BLINK_PUBLIC_PLATFORM_WEB_IMAGE_CAPTURE_FRAME_GRABBER_H_
 
+#include <memory>
+
 #include "third_party/blink/public/platform/web_callbacks.h"
 #include "third_party/blink/public/platform/web_common.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
@@ -22,8 +24,9 @@ class WebImageCaptureFrameGrabber {
  public:
   virtual ~WebImageCaptureFrameGrabber() = default;
 
-  virtual void GrabFrame(WebMediaStreamTrack*,
-                         WebImageCaptureGrabFrameCallbacks*) = 0;
+  virtual void GrabFrame(
+      WebMediaStreamTrack*,
+      std::unique_ptr<WebImageCaptureGrabFrameCallbacks> callbacks) = 0;
 };
 
 }  // namespace blink

third_party/blink/renderer/modules/imagecapture/image_capture.cc

@@ -313,8 +313,9 @@ ScriptPromise ImageCapture::grabFrame(ScriptState* script_state) {
 
   // The platform does not know about MediaStreamTrack, so we wrap it up.
   WebMediaStreamTrack track(stream_track_->Component());
-  frame_grabber_->GrabFrame(
-      &track, new CallbackPromiseAdapter<ImageBitmap, void>(resolver));
+  auto resolver_callback_adapter =
+      std::make_unique<CallbackPromiseAdapter<ImageBitmap, void>>(resolver);
+  frame_grabber_->GrabFrame(&track, std::move(resolver_callback_adapter));
 
   return promise;
 }