RenderWidgetCompositor should be decoupled from RenderWidget.

content/renderer/gpu/render_widget_compositor_delegate.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_RENDERER_GPU_RENDER_WIDGET_COMPOSITOR_DELEGATE_H_
+#define CONTENT_RENDERER_GPU_RENDER_WIDGET_COMPOSITOR_DELEGATE_H_
+
+#include "cc/debug/frame_timing_tracker.h"
+
+namespace blink {
+class WebWidget;
+struct WebScreenInfo;
+}
+
+namespace cc {
+class BeginFrameSource;
+class OutputSurface;
+}
+
+namespace content {
+
+// Consumers of RenderWidgetCompositor implement this delegate in order to
+// transport compositing information across processes.
+class CONTENT_EXPORT RenderWidgetCompositorDelegate {
+ public:
+  // Report viewport related properties during a commit from the compositor
+  // thread.
+  virtual void ApplyViewportDeltas(
+      const gfx::Vector2dF& inner_delta,
+      const gfx::Vector2dF& outer_delta,
+      const gfx::Vector2dF& elastic_overscroll_delta,
+      float page_scale,
+      float top_controls_delta) = 0;
+
+  // Notifies that the compositor has issed a BeginMainFrame.
+  virtual void BeginMainFrame(double frame_time_sec) = 0;
+
+  // Requests an OutputSurface to render into.
+  virtual scoped_ptr<cc::OutputSurface> CreateOutputSurface(bool fallback) = 0;
+
+  // Requests an external BeginFrameSource from the delegate.
+  virtual scoped_ptr<cc::BeginFrameSource> CreateExternalBeginFrameSource() = 0;
+
+  // Notifies that the draw commands for a committed frame have been issued.
+  virtual void DidCommitAndDrawCompositorFrame() = 0;
+
+  // Notifies about a compositor frame commit operation having finished.
+  virtual void DidCommitCompositorFrame() = 0;
+
+  // Called by the compositor when page scale animation completed.
+  virtual void DidCompletePageScaleAnimation() = 0;
+
+  // Notifies that the compositor has posted a swapbuffers operation to the GPU
+  // process.
+  virtual void DidCompleteSwapBuffers() = 0;
+
+  // TODO(simonhong, fsamuel): Remove this once crbug.com/471411 is resolved.
+  // Indicates whether this RenderWidgetCompositor is for an out-of-process
+  // iframe or not.
+  virtual bool ForOOPIF() const = 0;
+
+  // Called by the compositor to forward a proto that represents serialized
+  // compositor state.
+  virtual void ForwardCompositorProto(const std::vector<uint8_t>& proto) = 0;
+
+  // Called by the compositor in single-threaded mode when a swap is aborted.
+  virtual void OnSwapBuffersAborted() = 0;
+
+  // Called by the compositor in single-threaded mode when a swap completes.
+  virtual void OnSwapBuffersComplete() = 0;
+
+  // Called by the compositor in single-threaded mode when a swap is posted.
+  virtual void OnSwapBuffersPosted() = 0;
+
+  // Called by the compositor to request the delegate to record frame timing.
+  virtual void RecordFrameTimingEvents(
+      scoped_ptr<cc::FrameTimingTracker::CompositeTimingSet> composite_events,
+      scoped_ptr<cc::FrameTimingTracker::MainFrameTimingSet>
+          main_frame_events) = 0;
+
+  // Requests that the client schedule a composite now, and calculate
+  // appropriate delay for potential future frame.
+  virtual void ScheduleAnimation() = 0;
+
+  // Indicates that the compositor is about to begin a frame. This is primarily
+  // to signal to flow control mechanisms that a frame is beginning, not to
+  // perform actual painting work.
+  virtual void WillBeginCompositorFrame() = 0;
+
+ protected:
+  virtual ~RenderWidgetCompositorDelegate() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_GPU_RENDER_WIDGET_COMPOSITOR_DELEGATE_H_