cc: Send BeginFrame to VideoFrameController when added if we're inside a frame.

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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 "cc/trees/layer_tree_host_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <set>
@@ skipping 3066 matching lines @@
 }
 
 void LayerTreeHostImpl::SetNeedsRedrawForScrollbarAnimation() {
   SetNeedsRedraw();
 }
 
 void LayerTreeHostImpl::AddVideoFrameController(
     VideoFrameController* controller) {
   bool was_empty = video_frame_controllers_.empty();
   video_frame_controllers_.insert(controller);
+  if (current_begin_frame_args_.IsValid())
+    controller->OnBeginFrame(current_begin_frame_args_);

[brianderson, 2015/05/04 23:39:47]

Not that the controller is really going to care, but should we set the type to
MISSED before forwarding it to the controller?

Fine with holding off on this until the controller actually wants to use it.
Especially since we'd get this for free if/when the BeginFrameSource supports
multiple subscribers.

[sunnyps, 2015/05/04 23:41:06]

Yeah, let's hold off on this until we need it.

   if (was_empty)
     client_->SetVideoNeedsBeginFrames(true);
 }
 
 void LayerTreeHostImpl::RemoveVideoFrameController(
     VideoFrameController* controller) {
   video_frame_controllers_.erase(controller);
   if (video_frame_controllers_.empty())
     client_->SetVideoNeedsBeginFrames(false);
 }
@@ skipping 277 matching lines @@
   new_target.SetToMin(layer_impl->MaxScrollOffset());
 
   curve->UpdateTarget(
       animation->TrimTimeToCurrentIteration(CurrentBeginFrameArgs().frame_time)
           .InSecondsF(),
       new_target);
 
   return true;
 }
 }  // namespace cc