Limit outstanding surface draw swaps to max_frames_pending.

content/browser/compositor/onscreen_display_client.cc

Index: content/browser/compositor/onscreen_display_client.cc
diff --git a/content/browser/compositor/onscreen_display_client.cc b/content/browser/compositor/onscreen_display_client.cc
index da60316490f034c0e8f530e1a0b713dcca816173..2ca7a75bd67dd90545beb10b516f122f47b069a6 100644
--- a/content/browser/compositor/onscreen_display_client.cc
+++ b/content/browser/compositor/onscreen_display_client.cc
@@ -21,6 +21,8 @@ OnscreenDisplayClient::OnscreenDisplayClient(
           new cc::Display(this, manager, HostSharedBitmapManager::current())),
       task_runner_(task_runner),
       scheduled_draw_(false),
+      deferred_draw_(false),
+      pending_frames_(0),
       weak_ptr_factory_(this) {
 }
 
@@ -33,9 +35,19 @@ scoped_ptr<cc::OutputSurface> OnscreenDisplayClient::CreateOutputSurface() {
 }
 
 void OnscreenDisplayClient::DisplayDamaged() {
-  if (scheduled_draw_)
+  if (scheduled_draw_ || deferred_draw_)
     return;
   TRACE_EVENT0("content", "OnscreenDisplayClient::DisplayDamaged");
+  if (pending_frames_ >= display_->GetMaxFramesPending()) {
+    deferred_draw_ = true;
+  } else {
+    ScheduleDraw();
+  }
+}
+
+void OnscreenDisplayClient::ScheduleDraw() {
+  DCHECK(!deferred_draw_);
+  DCHECK(!scheduled_draw_);
   scheduled_draw_ = true;
   task_runner_->PostTask(
       FROM_HERE,
@@ -48,4 +60,16 @@ void OnscreenDisplayClient::Draw() {
   display_->Draw();
 }
 
+void OnscreenDisplayClient::DidSwapBuffers() {
+  pending_frames_++;
+}
+
+void OnscreenDisplayClient::DidSwapBuffersComplete() {
+  pending_frames_--;
+  if ((pending_frames_ < display_->GetMaxFramesPending()) && deferred_draw_) {
+    deferred_draw_ = false;
+    ScheduleDraw();
+  }
+}
+
 }  // namespace content