Display skips swapping if overlays draw the damage

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 "base/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/debug/benchmark_instrumentation.h"
 #include "cc/output/compositor_frame.h"
@@ skipping 221 matching lines @@
                      have_copy_requests || (have_damage && size_matches);
 
   // If the surface is suspended then the resources to be used by the draw are
   // likely destroyed.
   if (output_surface_->SurfaceIsSuspendForRecycle()) {
     TRACE_EVENT_INSTANT0("cc", "Surface is suspended for recycle.",
                          TRACE_EVENT_SCOPE_THREAD);
     should_draw = false;
   }
 
+  DrawFrameResult draw_result = DrawFrameResult::DID_DRAW;
   if (should_draw) {
     gfx::Rect device_viewport_rect = gfx::Rect(current_surface_size_);
     gfx::Rect device_clip_rect =
         external_clip_.IsEmpty() ? device_viewport_rect : external_clip_;
     bool disable_picture_quad_image_filtering = false;
 
     renderer_->DecideRenderPassAllocationsForFrame(
         frame_data->render_pass_list);
-    renderer_->DrawFrame(&frame_data->render_pass_list, device_scale_factor_,
-                         device_viewport_rect, device_clip_rect,
-                         disable_picture_quad_image_filtering);
+    draw_result = renderer_->DrawFrame(&frame_data->render_pass_list,
+                                       device_scale_factor_,
+                                       device_viewport_rect, device_clip_rect,
+                                       disable_picture_quad_image_filtering);
   } else {
     TRACE_EVENT_INSTANT0("cc", "Draw skipped.", TRACE_EVENT_SCOPE_THREAD);
   }
 
-  bool should_swap = should_draw && size_matches;
+  // If drawing was skipped because overlays removed the damage, swapping should
+  // be skipped too.
+  bool should_skip_swap =
+      have_damage && draw_result == DrawFrameResult::DAMAGE_DRAWN_BY_OVERLAYS &&
+      output_surface_->capabilities().schedules_overlays_without_swap;
+  bool should_swap = should_draw && size_matches && !should_skip_swap;
   if (should_swap) {
     swapped_since_resize_ = true;
     for (auto& latency : frame->metadata.latency_info) {
       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");
     }
     benchmark_instrumentation::IssueDisplayRenderingStatsEvent();
     renderer_->SwapBuffers(frame->metadata);
@@ skipping 85 matching lines @@
 
   if (surface_id == current_surface_id_)
     UpdateRootSurfaceResourcesLocked();
 }
 
 SurfaceId Display::CurrentSurfaceId() {
   return current_surface_id_;
 }
 
 }  // namespace cc