Hook up ui::Compositor to Display's BeginFrameSource

components/mus/surfaces/direct_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 "components/mus/surfaces/direct_output_surface.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/context_provider.h"
 #include "cc/output/output_surface_client.h"
 #include "gpu/command_buffer/client/context_support.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 
 namespace mus {
 
 DirectOutputSurface::DirectOutputSurface(
-    const scoped_refptr<cc::ContextProvider>& context_provider)
-    : cc::OutputSurface(context_provider), weak_ptr_factory_(this) {}
+    scoped_refptr<SurfacesContextProvider> context_provider,
+    base::SingleThreadTaskRunner* task_runner)
+    : cc::OutputSurface(context_provider),
+      synthetic_begin_frame_source_(new cc::SyntheticBeginFrameSource(
+          task_runner,
+          cc::BeginFrameArgs::DefaultInterval())),
+      weak_ptr_factory_(this) {
+  context_provider->SetDelegate(this);
+}
 
 DirectOutputSurface::~DirectOutputSurface() {}
 
 bool DirectOutputSurface::BindToClient(cc::OutputSurfaceClient* client) {
   if (!cc::OutputSurface::BindToClient(client))
     return false;
 
+  client->SetBeginFrameSource(synthetic_begin_frame_source_.get());
+
   if (capabilities_.uses_default_gl_framebuffer) {
     capabilities_.flipped_output_surface =
         context_provider()->ContextCapabilities().gpu.flips_vertically;
   }
   return true;
 }
 
+void DirectOutputSurface::OnVSyncParametersUpdated(int64_t timebase,
+                                                   int64_t interval) {
+  auto timebase_time_ticks = base::TimeTicks::FromInternalValue(timebase);

[sunnyps, 2016/04/01 22:35:25]

nit: Don't really need the _time_ticks and _time_delta suffixes.

[enne (OOO), 2016/04/02 00:18:38]

This code was moved from TopLevelDisplayClient, and those suffixes differentiate
from the function parameters.  Do you have a suggestion on what I should call
this if you don't like this code?

[sunnyps, 2016/04/02 00:47:15]

ah, ok nvm.

+  auto interval_time_delta = base::TimeDelta::FromInternalValue(interval);
+
+  if (interval_time_delta.is_zero()) {
+    // TODO(brianderson): We should not be receiving 0 intervals.
+    interval_time_delta = cc::BeginFrameArgs::DefaultInterval();
+  }
+
+  synthetic_begin_frame_source_->OnUpdateVSyncParameters(timebase_time_ticks,
+                                                         interval_time_delta);
+}
+
 void DirectOutputSurface::SwapBuffers(cc::CompositorFrame* frame) {
   DCHECK(context_provider_);
   DCHECK(frame->gl_frame_data);
   if (frame->gl_frame_data->sub_buffer_rect ==
       gfx::Rect(frame->gl_frame_data->size)) {
     context_provider_->ContextSupport()->Swap();
   } else {
     context_provider_->ContextSupport()->PartialSwapBuffers(
         frame->gl_frame_data->sub_buffer_rect);
   }
 
   gpu::gles2::GLES2Interface* gl = context_provider_->ContextGL();
   const GLuint64 fence_sync = gl->InsertFenceSyncCHROMIUM();
   gl->ShallowFlushCHROMIUM();
 
   gpu::SyncToken sync_token;
   gl->GenUnverifiedSyncTokenCHROMIUM(fence_sync, sync_token.GetData());
 
   context_provider_->ContextSupport()->SignalSyncToken(
       sync_token, base::Bind(&OutputSurface::OnSwapBuffersComplete,
                              weak_ptr_factory_.GetWeakPtr()));
   client_->DidSwapBuffers();
 }
 
 }  // namespace mus