cc: If SetDeferCommits(true) happens inside the main frame, abort it.

cc/trees/proxy_main.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_main.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/memory/ptr_util.h"
@@ skipping 169 matching lines @@
   layer_tree_host_->BeginMainFrame(begin_main_frame_state->begin_frame_args);
   layer_tree_host_->AnimateLayers(
       begin_main_frame_state->begin_frame_args.frame_time);
 
   // Recreate all UI resources if there were evicted UI resources when the impl
   // thread initiated the commit.
   if (begin_main_frame_state->evicted_ui_resources)
     layer_tree_host_->GetUIResourceManager()->RecreateUIResources();
 
   layer_tree_host_->RequestMainFrameUpdate();
+
+  // At this point the main frame may have deferred commits to avoid committing
+  // right now.
+  if (defer_commits_) {
+    TRACE_EVENT_INSTANT0("cc", "EarlyOut_DeferCommit_InsideBeginMainFrame",
+                         TRACE_EVENT_SCOPE_THREAD);
+    std::vector<std::unique_ptr<SwapPromise>> empty_swap_promises;
+    ImplThreadTaskRunner()->PostTask(
+        FROM_HERE, base::Bind(&ProxyImpl::BeginMainFrameAbortedOnImpl,
+                              base::Unretained(proxy_impl_.get()),
+                              CommitEarlyOutReason::ABORTED_DEFERRED_COMMIT,
+                              begin_main_frame_start_time,
+                              base::Passed(&empty_swap_promises)));
+    current_pipeline_stage_ = NO_PIPELINE_STAGE;
+    // We intentionally don't report CommitComplete() here since it was aborted
+    // prematurely and we're waiting to do another commit in the future.
+    layer_tree_host_->DidBeginMainFrame();
+    return;
+  }
+
   TRACE_EVENT_SYNTHETIC_DELAY_END("cc.BeginMainFrame");
 
   bool can_cancel_this_commit = final_pipeline_stage_ < COMMIT_PIPELINE_STAGE &&
                                 !begin_main_frame_state->evicted_ui_resources;
 
   current_pipeline_stage_ = UPDATE_LAYERS_PIPELINE_STAGE;
   bool should_update_layers =
       final_pipeline_stage_ >= UPDATE_LAYERS_PIPELINE_STAGE;
   bool updated = should_update_layers && layer_tree_host_->UpdateLayers();
 
@@ skipping 285 matching lines @@
 
 bool ProxyMain::IsImplThread() const {
   return task_runner_provider_->IsImplThread();
 }
 
 base::SingleThreadTaskRunner* ProxyMain::ImplThreadTaskRunner() {
   return task_runner_provider_->ImplThreadTaskRunner();
 }
 
 }  // namespace cc