cc: Add support for handling authoritative vsync interval

cc/scheduler/scheduler_unittest.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/scheduler/scheduler.h"
 
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 2254 matching lines @@
   EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
   EXPECT_TRUE(scheduler_->BeginImplFrameDeadlinePending());
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("SetNeedsBeginFrames(false)", client_, 0, 2);
   EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 1, 2);
   client_->Reset();
 }
 
+TEST_F(SchedulerTest, AuthoritativeVSyncInterval) {
+  SetUpScheduler(true);
+
+  base::TimeDelta initial_interval =
+      scheduler_->begin_impl_frame_args().interval;
+  base::TimeDelta authoritative_interval =
+      base::TimeDelta::FromMilliseconds(33);
+
+  scheduler_->SetNeedsCommit();
+  EXPECT_SCOPED(AdvanceFrame());
+
+  EXPECT_EQ(initial_interval, scheduler_->begin_impl_frame_args().interval);
+
+  scheduler_->NotifyBeginMainFrameStarted();
+  scheduler_->NotifyReadyToCommit();
+  task_runner().RunTasksWhile(client_->ImplFrameDeadlinePending(true));
+
+  scheduler_->SetAuthoritativeVSyncInterval(authoritative_interval);
+
+  EXPECT_SCOPED(AdvanceFrame());
+
+  // At the next BeginFrame, authoritative interval is used instead of previous
+  // interval.
+  EXPECT_NE(initial_interval, scheduler_->begin_impl_frame_args().interval);
+  EXPECT_EQ(authoritative_interval,
+            scheduler_->begin_impl_frame_args().interval);
+}
+
 }  // namespace
 }  // namespace cc