Splitting DidSwap in cc::SwapPromise into WillSwap and DidSwap

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 1648 matching lines @@
   }
 
 
   CompositorFrame compositor_frame;
   compositor_frame.metadata = std::move(metadata);
   resource_provider_->PrepareSendToParent(resources,
                                           &compositor_frame.resource_list);
   compositor_frame.render_pass_list = std::move(frame->render_passes);
   compositor_frame_sink_->SubmitCompositorFrame(std::move(compositor_frame));
 
+  // Clears the list of swap promises after calling DidSwap on each of them to
+  // signal that the swap is over.
+  active_tree()->ClearSwapPromises();
+
   // 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();
 
@@ skipping 2405 matching lines @@
       worker_context_visibility_ =
           worker_context->CacheController()->ClientBecameVisible();
     } else {
       worker_context->CacheController()->ClientBecameNotVisible(
           std::move(worker_context_visibility_));
     }
   }
 }
 
 }  // namespace cc