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_));
 
-  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));
+  // 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_.get());
+  DCHECK(!layer_tree_host->settings().use_output_surface_begin_frame_source ||
+         !external_begin_frame_source_.get());
+  scheduler_ = Scheduler::Create(this, scheduler_settings, layer_tree_host_id_,
+                                 task_runner_provider_->ImplThreadTaskRunner(),
+                                 external_begin_frame_source_.get(),
+                                 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() {
@@ skipping 551 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