Ozone: Avoid blocking in Swapbuffer Call.

content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc

 // Copyright 2014 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/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.h"
 
 #include "cc/output/compositor_frame.h"
 #include "content/browser/compositor/buffer_queue.h"
 #include "content/browser/compositor/reflector_impl.h"
 #include "content/browser/gpu/gpu_surface_tracker.h"
@@ skipping 12 matching lines @@
         const scoped_refptr<ui::CompositorVSyncManager>& vsync_manager,
         scoped_ptr<cc::OverlayCandidateValidator> overlay_candidate_validator,
         unsigned internalformat,
         bool use_own_gl_helper)
     : GpuBrowserCompositorOutputSurface(context,
                                         surface_id,
                                         output_surface_map,
                                         vsync_manager,
                                         overlay_candidate_validator.Pass()),
       internalformat_(internalformat),
-      use_own_gl_helper_(use_own_gl_helper) {
+      use_own_gl_helper_(use_own_gl_helper),
+      page_flip_completion_callback_(
+          base::Bind(&GpuSurfacelessBrowserCompositorOutputSurface::
+              OnPageFlipCompleted, base::Unretained(this))) {
   capabilities_.uses_default_gl_framebuffer = false;
   capabilities_.flipped_output_surface = true;
 }
 
 GpuSurfacelessBrowserCompositorOutputSurface::
     ~GpuSurfacelessBrowserCompositorOutputSurface() {

[alexst (slow to review), 2014/12/10 23:19:25]

Should the callback be reset here?

 }
 
 void GpuSurfacelessBrowserCompositorOutputSurface::SwapBuffers(
     cc::CompositorFrame* frame) {
   DCHECK(output_surface_);
 
   GLuint texture = output_surface_->current_texture_id();
   output_surface_->SwapBuffers(frame->gl_frame_data->sub_buffer_rect);
   const gfx::Size& size = frame->gl_frame_data->size;
   context_provider_->ContextGL()->ScheduleOverlayPlaneCHROMIUM(
       0,
       GL_OVERLAY_TRANSFORM_NONE_CHROMIUM,
       texture,
       0,
       0,
       size.width(),
       size.height(),
       0,
       0,
       1.0f,
       1.0f);
   GpuBrowserCompositorOutputSurface::SwapBuffers(frame);
 }
 
 void GpuSurfacelessBrowserCompositorOutputSurface::OnSwapBuffersComplete() {
   DCHECK(output_surface_);
-  output_surface_->PageFlipComplete();
   GpuBrowserCompositorOutputSurface::OnSwapBuffersComplete();
 }
 
 void GpuSurfacelessBrowserCompositorOutputSurface::BindFramebuffer() {
   DCHECK(output_surface_);
   output_surface_->BindFramebuffer();
 }
 
 void GpuSurfacelessBrowserCompositorOutputSurface::Reshape(
     const gfx::Size& size,
@@ skipping 13 matching lines @@
                                   context_provider_->ContextSupport()));
     helper = gl_helper_.get();
   } else {
     helper = ImageTransportFactory::GetInstance()->GetGLHelper();
   }
   if (!helper)
     return false;
 
   output_surface_.reset(
       new BufferQueue(context_provider_, internalformat_, helper));
+
+  GetCommandBufferProxy()->SetPageFlipCompletionCallback(
+      page_flip_completion_callback_.callback());

[alexst (slow to review), 2014/12/10 23:19:25]

Why not base::Bind(&BufferQueue::PageFlipComplete,
base::Unretained(output_surface_.get())) here instead?

[kalyank, 2014/12/11 12:55:58]

Done.

+
   return output_surface_->Initialize();
 }
 
+void GpuSurfacelessBrowserCompositorOutputSurface::OnPageFlipCompleted() {
+  output_surface_->PageFlipComplete();
+}
+
 }  // namespace content