sync compositor: Reduce begin frame sync IPC overhead

content/browser/android/synchronous_compositor_host.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 "content/browser/android/synchronous_compositor_host.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/shared_memory.h"
 #include "base/trace_event/trace_event_argument.h"
+#include "content/browser/android/synchronous_compositor_observer.h"
 #include "content/browser/renderer_host/render_widget_host_view_android.h"
 #include "content/browser/web_contents/web_contents_android.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/android/sync_compositor_messages.h"
 #include "content/common/android/sync_compositor_statics.h"
 #include "content/public/browser/android/synchronous_compositor_client.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/common/content_switches.h"
 #include "ipc/ipc_sender.h"
@@ skipping 37 matching lines @@
 
 SynchronousCompositorHost::SynchronousCompositorHost(
     RenderWidgetHostViewAndroid* rwhva,
     SynchronousCompositorClient* client,
     bool use_in_proc_software_draw)
     : rwhva_(rwhva),
       client_(client),
       ui_task_runner_(BrowserThread::GetTaskRunnerForThread(BrowserThread::UI)),
       process_id_(rwhva_->GetRenderWidgetHost()->GetProcess()->GetID()),
       routing_id_(rwhva_->GetRenderWidgetHost()->GetRoutingID()),
+      rph_observer_(SynchronousCompositorObserver::GetOrCreateFor(process_id_)),
       sender_(rwhva_->GetRenderWidgetHost()),
       use_in_process_zero_copy_software_draw_(use_in_proc_software_draw),
       bytes_limit_(0u),
       renderer_param_version_(0u),
       need_animate_scroll_(false),
       need_invalidate_count_(0u),
       did_activate_pending_tree_count_(0u) {
   client_->DidInitializeCompositor(this, process_id_, routing_id_);
 }
 
@@ skipping 249 matching lines @@
       new SyncCompositorMsg_ComputeScroll(routing_id_, animation_time));
 }
 
 void SynchronousCompositorHost::DidOverscroll(
     const DidOverscrollParams& over_scroll_params) {
   client_->DidOverscroll(this, over_scroll_params.accumulated_overscroll,
                          over_scroll_params.latest_overscroll_delta,
                          over_scroll_params.current_fling_velocity);
 }
 
-void SynchronousCompositorHost::DidSendBeginFrame() {
-  SyncCompositorCommonRendererParams common_renderer_params;
-  if (!sender_->Send(new SyncCompositorMsg_SynchronizeRendererState(
-          routing_id_, &common_renderer_params))) {
-    return;
-  }
-  ProcessCommonParams(common_renderer_params);
+void SynchronousCompositorHost::DidSendBeginFrame(
+    ui::WindowAndroid* window_android) {
+  rph_observer_->SyncStateAfterVSync(window_android, this);
 }
 
 void SynchronousCompositorHost::OutputSurfaceCreated() {
   // New output surface is not aware of state from Browser side. So need to
   // re-send all browser side state here.
   sender_->Send(
       new SyncCompositorMsg_SetMemoryPolicy(routing_id_, bytes_limit_));
 }
 
 void SynchronousCompositorHost::ProcessCommonParams(
@@ skipping 24 matching lines @@
   if (params.page_scale_factor) {
     client_->UpdateRootLayerState(
         this, gfx::ScrollOffsetToVector2dF(params.total_scroll_offset),
         gfx::ScrollOffsetToVector2dF(params.max_scroll_offset),
         params.scrollable_size, params.page_scale_factor,
         params.min_page_scale_factor, params.max_page_scale_factor);
   }
 }
 
 }  // namespace content