cc: Merge the DrawLayer()/DrawFrame() and SwapBuffers() methods.

cc/trees/layer_tree_host_impl.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/trees/layer_tree_host_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 1606 matching lines @@
   metadata.root_overflow_y_hidden |=
       !InnerViewportScrollLayer()->user_scrollable_vertical();
 
   // TODO(miletus) : Change the metadata to hold ScrollOffset.
   metadata.root_scroll_offset =
       gfx::ScrollOffsetToVector2dF(active_tree_->TotalScrollOffset());
 
   return metadata;
 }
 
-void LayerTreeHostImpl::DrawLayers(FrameData* frame) {
+bool LayerTreeHostImpl::DrawLayers(FrameData* frame) {
+  DCHECK(CanDraw());
+  DCHECK_EQ(frame->has_no_damage, frame->render_passes.empty());
+
   TRACE_EVENT0("cc", "LayerTreeHostImpl::DrawLayers");
 
-  base::TimeTicks frame_begin_time = CurrentBeginFrameArgs().frame_time;
-  DCHECK(CanDraw());
+  ResetRequiresHighResToDraw();
 
   if (frame->has_no_damage) {
+    DCHECK(!resourceless_software_draw_);
+
     TRACE_EVENT_INSTANT0("cc", "EarlyOut_NoDamage", TRACE_EVENT_SCOPE_THREAD);
-    DCHECK(!resourceless_software_draw_);
-    return;
+    active_tree()->BreakSwapPromises(SwapPromise::SWAP_FAILS);
+    return false;
   }
 
-  DCHECK(!frame->render_passes.empty());
-
-  fps_counter_->SaveTimeStamp(frame_begin_time,
+  fps_counter_->SaveTimeStamp(CurrentBeginFrameArgs().frame_time,
                               !output_surface_->context_provider());
   rendering_stats_instrumentation_->IncrementFrameCount(1);
 
   memory_history_->SaveEntry(tile_manager_.memory_stats_from_last_assign());
 
   if (debug_state_.ShowHudRects()) {
     debug_rect_history_->SaveDebugRectsForCurrentFrame(
         active_tree(), active_tree_->hud_layer(),
         *frame->render_surface_layer_list, debug_state_);
   }
@@ skipping 20 matching lines @@
 
   // Because the contents of the HUD depend on everything else in the frame, the
   // contents of its texture are updated as the last thing before the frame is
   // drawn.
   if (active_tree_->hud_layer()) {
     TRACE_EVENT0("cc", "DrawLayers.UpdateHudTexture");
     active_tree_->hud_layer()->UpdateHudTexture(draw_mode,
                                                 resource_provider_.get());
   }
 
-  renderer_->DrawFrame(&frame->render_passes);
-  // The render passes should be consumed by the renderer.
-  DCHECK(frame->render_passes.empty());
+  CompositorFrameMetadata metadata = MakeCompositorFrameMetadata();
+  metadata.may_contain_video = frame->may_contain_video;
+  active_tree()->FinishSwapPromises(&metadata);
+  for (auto& latency : 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", "SwapBuffers");
+    // Only add the latency component once for renderer swap, not the browser
+    // swap.
+    if (!latency.FindLatency(ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT, 0,
+                             nullptr)) {
+      latency.AddLatencyNumber(ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT,
+                               0, 0);
+    }
+  }
+
+  renderer_->DrawFrame(std::move(metadata), std::move(frame->render_passes));
+
+  // The next frame should start by assuming nothing has changed, and changes
+  // are noted as they occur.
+  // TODO(boliu): If we did a temporary software renderer frame, propogate the
+  // damage forward to the next frame.
+  for (size_t i = 0; i < frame->render_surface_layer_list->size(); i++) {
+    auto* surface = (*frame->render_surface_layer_list)[i]->render_surface();
+    surface->damage_tracker()->DidDrawDamagedArea();
+  }
+  active_tree_->ResetAllChangeTracking();
+
+  active_tree_->set_has_ever_been_drawn(true);
+  devtools_instrumentation::DidDrawFrame(id_);
+  benchmark_instrumentation::IssueImplThreadRenderingStatsEvent(
+      rendering_stats_instrumentation_->impl_thread_rendering_stats());
+  rendering_stats_instrumentation_->AccumulateAndClearImplThreadStats();
+  return true;
 }
 
 void LayerTreeHostImpl::DidDrawAllLayers(const FrameData& frame) {
   for (size_t i = 0; i < frame.will_draw_layers.size(); ++i)
     frame.will_draw_layers[i]->DidDraw(resource_provider_.get());
 
   for (auto* it : video_frame_controllers_)
     it->DidDrawFrame();
 }
 
@@ skipping 118 matching lines @@
   }
   RecreateTreeResources();
 
   // We have released tilings for both active and pending tree.
   // We would not have any content to draw until the pending tree is activated.
   // Prevent the active tree from drawing until activation.
   // TODO(crbug.com/469175): Replace with RequiresHighResToDraw.
   SetRequiresHighResToDraw();
 }
 
-bool LayerTreeHostImpl::SwapBuffers(const LayerTreeHostImpl::FrameData& frame) {
-  ResetRequiresHighResToDraw();
-
-  if (frame.has_no_damage) {
-    active_tree()->BreakSwapPromises(SwapPromise::SWAP_FAILS);
-    return false;
-  }
-
-  CompositorFrameMetadata metadata = MakeCompositorFrameMetadata();
-  metadata.may_contain_video = frame.may_contain_video;
-  active_tree()->FinishSwapPromises(&metadata);
-  for (auto& latency : 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", "SwapBuffers");
-    // Only add the latency component once for renderer swap, not the browser
-    // swap.
-    if (!latency.FindLatency(ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT, 0,
-                             nullptr)) {
-      latency.AddLatencyNumber(ui::INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT,
-                               0, 0);
-    }
-  }
-  renderer_->SwapBuffers(std::move(metadata));
-
-  // The next frame should start by assuming nothing has changed, and changes
-  // are noted as they occur.
-  // TODO(boliu): If we did a temporary software renderer frame, propogate the
-  // damage forward to the next frame.
-  for (size_t i = 0; i < frame.render_surface_layer_list->size(); i++) {
-    auto* surface = (*frame.render_surface_layer_list)[i]->render_surface();
-    surface->damage_tracker()->DidDrawDamagedArea();
-  }
-  active_tree_->ResetAllChangeTracking();
-
-  active_tree_->set_has_ever_been_drawn(true);
-  devtools_instrumentation::DidDrawFrame(id_);
-  benchmark_instrumentation::IssueImplThreadRenderingStatsEvent(
-      rendering_stats_instrumentation_->impl_thread_rendering_stats());
-  rendering_stats_instrumentation_->AccumulateAndClearImplThreadStats();
-  return true;
-}
-
 void LayerTreeHostImpl::WillBeginImplFrame(const BeginFrameArgs& args) {
   current_begin_frame_tracker_.Start(args);
 
   if (is_likely_to_require_a_draw_) {
     // Optimistically schedule a draw. This will let us expect the tile manager
     // to complete its work so that we can draw new tiles within the impl frame
     // we are beginning now.
     SetNeedsRedraw();
   }
 
@@ skipping 2319 matching lines @@
   if (is_visible) {
     worker_context_visibility_ =
         worker_context->CacheController()->ClientBecameVisible();
   } else {
     worker_context->CacheController()->ClientBecameNotVisible(
         std::move(worker_context_visibility_));
   }
 }
 
 }  // namespace cc