CrOS: Set max frames pending for UI from command line.

cc/thread_proxy.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/thread_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "cc/context_provider.h"
@@ skipping 1103 matching lines @@
   TRACE_EVENT0("cc", "ThreadProxy::InitializeRendererOnImplThread");
   DCHECK(IsImplThread());
   DCHECK(output_surface_before_initialization_on_impl_thread_.get());
   *initialize_succeeded = layer_tree_host_impl_->InitializeRenderer(
       output_surface_before_initialization_on_impl_thread_.Pass());
   if (*initialize_succeeded) {
     *capabilities = layer_tree_host_impl_->GetRendererCapabilities();
     scheduler_on_impl_thread_->setSwapBuffersCompleteSupported(
         capabilities->using_swap_complete_callback);
 
-    int maxFramesPending = FrameRateController::kDefaultMaxFramesPending;
+    int maxFramesPending = layer_tree_host_impl_->output_surface()->
+        capabilities().max_frames_pending;
+    if (maxFramesPending <= 0)
+      maxFramesPending = FrameRateController::kDefaultMaxFramesPending;
     if (layer_tree_host_impl_->output_surface()->capabilities().
             has_parent_compositor)
       maxFramesPending = 1;
     scheduler_on_impl_thread_->setMaxFramesPending(maxFramesPending);
   }
 
   completion->signal();
 }
 
 void ThreadProxy::LayerTreeHostClosedOnImplThread(CompletionEvent* completion) {
@@ skipping 178 matching lines @@
 }
 
 void ThreadProxy::RenewTreePriorityOnImplThread() {
   DCHECK(renew_tree_priority_on_impl_thread_pending_);
   renew_tree_priority_on_impl_thread_pending_ = false;
 
   RenewTreePriority();
 }
 
 }  // namespace cc