[cc] Calculate the correct latest_confirmed_sequence_number in cc::Scheduler.

cc/test/scheduler_test_common.h

 // 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.
 
 #ifndef CC_TEST_SCHEDULER_TEST_COMMON_H_
 #define CC_TEST_SCHEDULER_TEST_COMMON_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 126 matching lines @@
   BeginFrameSource& frame_source() { return *begin_frame_source_; }
 
   bool MainThreadMissedLastDeadline() const {
     return state_machine_.main_thread_missed_last_deadline();
   }
 
   bool begin_frames_expected() const {
     return begin_frame_source_ && observing_begin_frame_source_;
   }
 
+  bool BeginFrameNeeded() const { return state_machine_.BeginFrameNeeded(); }
+
   int current_frame_number() const {
     return state_machine_.current_frame_number();
   }
 
   bool needs_impl_side_invalidation() const {
     return state_machine_.needs_impl_side_invalidation();
   }
 
   ~TestScheduler() override;
 
@@ skipping 15 matching lines @@
 
  private:
   base::SimpleTestTickClock* now_src_;
 
   DISALLOW_COPY_AND_ASSIGN(TestScheduler);
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_SCHEDULER_TEST_COMMON_H_