Reland of cc: Remove frame queuing from the scheduler.

cc/surfaces/display.cc

 // Copyright 2014 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/surfaces/display.h"
 
 #include <stddef.h>
 
 #include "base/memory/ptr_util.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 230 matching lines @@
   CompositorFrame frame = aggregator_->Aggregate(current_surface_id_);
   if (!frame.delegated_frame_data) {
     TRACE_EVENT_INSTANT0("cc", "Empty aggregated frame.",
                          TRACE_EVENT_SCOPE_THREAD);
     return false;
   }
 
   // Run callbacks early to allow pipelining.
   for (const auto& id_entry : aggregator_->previous_contained_surfaces()) {
     Surface* surface = surface_manager_->GetSurfaceForId(id_entry.first);
-    if (surface)
+    if (surface && surface->surface_id() != current_surface_id_)
       surface->RunDrawCallbacks();
   }
 
   DelegatedFrameData* frame_data = frame.delegated_frame_data.get();
 
   frame.metadata.latency_info.insert(frame.metadata.latency_info.end(),
                                      stored_latency_info_.begin(),
                                      stored_latency_info_.end());
   stored_latency_info_.clear();
   bool have_copy_requests = false;
@@ skipping 56 matching lines @@
                          device_color_space_, device_viewport_rect,
                          device_clip_rect);
   } else {
     TRACE_EVENT_INSTANT0("cc", "Draw skipped.", TRACE_EVENT_SCOPE_THREAD);
   }
 
   bool should_swap = should_draw && size_matches;
   if (should_swap) {
     swapped_since_resize_ = true;
     for (auto& latency : frame.metadata.latency_info) {
-      TRACE_EVENT_WITH_FLOW1("input,benchmark", "LatencyInfo.Flow",
+      TRACE_EVENT_WITH_FLOW1(
+          "input,benchmark", "LatencyInfo.Flow",
           TRACE_ID_DONT_MANGLE(latency.trace_id()),
-          TRACE_EVENT_FLAG_FLOW_IN | TRACE_EVENT_FLAG_FLOW_OUT,
-          "step", "Display::DrawAndSwap");
+          TRACE_EVENT_FLAG_FLOW_IN | TRACE_EVENT_FLAG_FLOW_OUT, "step",
+          "Display::DrawAndSwap");
     }
     benchmark_instrumentation::IssueDisplayRenderingStatsEvent();
     renderer_->SwapBuffers(std::move(frame.metadata));
     if (scheduler_)
       scheduler_->DidSwapBuffers();
   } else {
     if (have_damage && !size_matches)
       aggregator_->SetFullDamageForSurface(current_surface_id_);
     TRACE_EVENT_INSTANT0("cc", "Swap skipped.", TRACE_EVENT_SCOPE_THREAD);
     stored_latency_info_.insert(stored_latency_info_.end(),
                                 frame.metadata.latency_info.begin(),
                                 frame.metadata.latency_info.end());
     if (scheduler_) {
       scheduler_->DidSwapBuffers();
       scheduler_->DidSwapBuffersComplete();
     }
   }
 
+  // Run draw callback for root surface after drawing.

[enne (OOO), 2016/09/19 22:11:50]

Can you make this comment more of a 'why' and less of a 'what' so that future
engineers can understand why we break up the callbacks?

[sunnyps, 2016/09/19 23:59:04]

Added comment where we run the callbacks for other surfaces above.

+  Surface* root_surface =
+      surface_manager_->GetSurfaceForId(current_surface_id_);
+  if (root_surface)
+    root_surface->RunDrawCallbacks();
+
   client_->DisplayDidDrawAndSwap();
   return true;
 }
 
 void Display::DidSwapBuffersComplete() {
   if (scheduler_)
     scheduler_->DidSwapBuffersComplete();
   if (renderer_)
     renderer_->SwapBuffersComplete();
 }
@@ skipping 68 matching lines @@
 const SurfaceId& Display::CurrentSurfaceId() {
   return current_surface_id_;
 }
 
 void Display::ForceImmediateDrawAndSwapIfPossible() {
   if (scheduler_)
     scheduler_->ForceImmediateSwapIfPossible();
 }
 
 }  // namespace cc