Revert of Remove default begin frame sources from the renderer

cc/trees/proxy_impl.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 "cc/trees/proxy_impl.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/auto_reset.h"
@@ skipping 59 matching lines @@
 
   SchedulerSettings scheduler_settings(
       layer_tree_host->settings().ToSchedulerSettings());
 
   std::unique_ptr<CompositorTimingHistory> compositor_timing_history(
       new CompositorTimingHistory(
           scheduler_settings.using_synchronous_renderer_compositor,
           CompositorTimingHistory::RENDERER_UMA,
           rendering_stats_instrumentation_));
 
-  // BFS must either be external or come from the output surface.  If
-  // external, it must be provided.  If from the output surface, it must
-  // not be provided.
-  // TODO(enne): Make all BFS come from the output surface.
-  DCHECK(layer_tree_host->settings().use_external_begin_frame_source ^
-         layer_tree_host->settings().use_output_surface_begin_frame_source);
-  DCHECK(!layer_tree_host->settings().use_external_begin_frame_source ||
-         external_begin_frame_source_);
-  DCHECK(!layer_tree_host->settings().use_output_surface_begin_frame_source ||
-         !external_begin_frame_source_);
-  scheduler_ = Scheduler::Create(this, scheduler_settings, layer_tree_host_id_,
-                                 task_runner_provider_->ImplThreadTaskRunner(),
-                                 external_begin_frame_source_.get(),
-                                 std::move(compositor_timing_history));
+  BeginFrameSource* frame_source = external_begin_frame_source_.get();
+  if (!scheduler_settings.throttle_frame_production) {
+    // Unthrottled source takes precedence over external sources.
+    unthrottled_begin_frame_source_.reset(
+        new BackToBackBeginFrameSource(base::MakeUnique<DelayBasedTimeSource>(
+            task_runner_provider_->ImplThreadTaskRunner())));
+    frame_source = unthrottled_begin_frame_source_.get();
+  }
+  if (!frame_source) {
+    synthetic_begin_frame_source_.reset(
+        new DelayBasedBeginFrameSource(base::MakeUnique<DelayBasedTimeSource>(
+            task_runner_provider_->ImplThreadTaskRunner())));
+    frame_source = synthetic_begin_frame_source_.get();
+  }
+  scheduler_ =
+      Scheduler::Create(this, scheduler_settings, layer_tree_host_id_,
+                        task_runner_provider_->ImplThreadTaskRunner(),
+                        frame_source, std::move(compositor_timing_history));
 
   DCHECK_EQ(scheduler_->visible(), layer_tree_host_impl_->visible());
 }
 
 ProxyImpl::BlockedMainCommitOnly::BlockedMainCommitOnly()
     : layer_tree_host(nullptr) {}
 
 ProxyImpl::BlockedMainCommitOnly::~BlockedMainCommitOnly() {}
 
 ProxyImpl::~ProxyImpl() {
   TRACE_EVENT0("cc", "ProxyImpl::~ProxyImpl");
   DCHECK(IsImplThread());
   DCHECK(IsMainThreadBlocked());
 
   // Take away the OutputSurface before destroying things so it doesn't try
   // to call into its client mid-shutdown.
   scheduler_->DidLoseOutputSurface();
   layer_tree_host_impl_->ReleaseOutputSurface();
 
   scheduler_ = nullptr;
   external_begin_frame_source_ = nullptr;
+  unthrottled_begin_frame_source_ = nullptr;
+  synthetic_begin_frame_source_ = nullptr;
   layer_tree_host_impl_ = nullptr;
   // We need to explicitly shutdown the notifier to destroy any weakptrs it is
   // holding while still on the compositor thread. This also ensures any
   // callbacks holding a ProxyImpl pointer are cancelled.
   smoothness_priority_expiration_notifier_.Shutdown();
 }
 
 void ProxyImpl::InitializeMutatorOnImpl(
     std::unique_ptr<LayerTreeMutator> mutator) {
   TRACE_EVENT0("cc,compositor-worker", "ProxyImpl::InitializeMutatorOnImpl");
@@ skipping 139 matching lines @@
   scheduler_->NotifyReadyToCommit();
 }
 
 void ProxyImpl::DidLoseOutputSurfaceOnImplThread() {
   TRACE_EVENT0("cc", "ProxyImpl::DidLoseOutputSurfaceOnImplThread");
   DCHECK(IsImplThread());
   channel_impl_->DidLoseOutputSurface();
   scheduler_->DidLoseOutputSurface();
 }
 
+void ProxyImpl::CommitVSyncParameters(base::TimeTicks timebase,
+                                      base::TimeDelta interval) {
+  DCHECK(IsImplThread());
+  if (synthetic_begin_frame_source_)
+    synthetic_begin_frame_source_->OnUpdateVSyncParameters(timebase, interval);
+}
+
 void ProxyImpl::SetBeginFrameSource(BeginFrameSource* source) {
   // During shutdown, destroying the OutputSurface may unset the
   // BeginFrameSource.
   if (scheduler_) {
     // TODO(enne): this overrides any preexisting begin frame source.  Those
     // other sources will eventually be removed and this will be the only path.
     scheduler_->SetBeginFrameSource(source);
   }
 }
 
@@ skipping 348 matching lines @@
 bool ProxyImpl::IsMainThreadBlocked() const {
   return task_runner_provider_->IsMainThreadBlocked();
 }
 
 ProxyImpl::BlockedMainCommitOnly& ProxyImpl::blocked_main_commit() {
   DCHECK(IsMainThreadBlocked() && commit_completion_event_);
   return main_thread_blocked_commit_vars_unsafe_;
 }
 
 }  // namespace cc