Plumb activation time to main

cc/trees/proxy_impl.cc

 // 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.
 
 #include "cc/trees/proxy_impl.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/auto_reset.h"
@@ skipping 557 matching lines @@
   layer_tree_host_impl_->InvalidateContentOnImplSide();
 }
 
 void ProxyImpl::SendBeginMainFrameNotExpectedSoon() {
   DCHECK(IsImplThread());
   MainThreadTaskRunner()->PostTask(
       FROM_HERE, base::Bind(&ProxyMain::BeginMainFrameNotExpectedSoon,
                             proxy_main_weak_ptr_));
 }
 
+int ProxyImpl::SyncTreeSourceFrameNumber() {

[vmpstr, 2017/04/05 19:11:33]

Based on the name, is this meant to check LTHI::sync_tree()? Although this would
erroneously return the active tree if the pending tree doesn't exist... So maybe
this is good

[panicker, 2017/04/08 00:29:07]

I do want the pending tree. Should I rename the method?

+  if (layer_tree_host_impl_->pending_tree())
+    return layer_tree_host_impl_->pending_tree()->source_frame_number();
+  else
+    return 0;
+}
+
 DrawResult ProxyImpl::DrawInternal(bool forced_draw) {
   TRACE_EVENT_SYNTHETIC_DELAY("cc.Draw");
 
   DCHECK(IsImplThread());
   DCHECK(layer_tree_host_impl_.get());
 
   base::AutoReset<bool> mark_inside(&inside_draw_, true);
 
   if (layer_tree_host_impl_->pending_tree()) {
     bool update_lcd_text = false;
@@ skipping 61 matching lines @@
 ProxyImpl::BlockedMainCommitOnly& ProxyImpl::blocked_main_commit() {
   DCHECK(IsMainThreadBlocked() && commit_completion_event_);
   return main_thread_blocked_commit_vars_unsafe_;
 }
 
 base::SingleThreadTaskRunner* ProxyImpl::MainThreadTaskRunner() {
   return task_runner_provider_->MainThreadTaskRunner();
 }
 
 }  // namespace cc