Refactoring the way begin frame sources inside scheduler work.

cc/BUILD.gn

 # Copyright 2014 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.
 
 component("cc") {
   sources = [
     "animation/animation.cc",
     "animation/animation.h",
     "animation/animation_curve.cc",
     "animation/animation_curve.h",
@@ skipping 261 matching lines @@
     "output/shader.cc",
     "output/shader.h",
     "output/software_frame_data.cc",
     "output/software_frame_data.h",
     "output/software_output_device.cc",
     "output/software_output_device.h",
     "output/software_renderer.cc",
     "output/software_renderer.h",
     "output/viewport_selection_bound.cc",
     "output/viewport_selection_bound.h",
+    "output/vsync_parameter_observer.h",
     "quads/checkerboard_draw_quad.cc",
     "quads/checkerboard_draw_quad.h",
     "quads/content_draw_quad_base.cc",
     "quads/content_draw_quad_base.h",
     "quads/debug_border_draw_quad.cc",
     "quads/debug_border_draw_quad.h",
     "quads/draw_polygon.cc",
     "quads/draw_polygon.h",
     "quads/draw_quad.cc",
     "quads/draw_quad.h",
@@ skipping 131 matching lines @@
     "resources/transferable_resource.h",
     "resources/ui_resource_bitmap.cc",
     "resources/ui_resource_bitmap.h",
     "resources/ui_resource_client.h",
     "resources/ui_resource_request.cc",
     "resources/ui_resource_request.h",
     "resources/video_resource_updater.cc",
     "resources/video_resource_updater.h",
     "resources/zero_copy_raster_worker_pool.cc",
     "resources/zero_copy_raster_worker_pool.h",
+    "scheduler/begin_frame_source.cc",
+    "scheduler/begin_frame_source.h",
     "scheduler/delay_based_time_source.cc",
     "scheduler/delay_based_time_source.h",
     "scheduler/draw_result.h",
     "scheduler/scheduler.cc",
     "scheduler/scheduler.h",
     "scheduler/scheduler_settings.cc",
     "scheduler/scheduler_settings.h",
     "scheduler/scheduler_state_machine.cc",
     "scheduler/scheduler_state_machine.h",
     "trees/blocking_task_runner.cc",
@@ skipping 283 matching lines @@
     "resources/raster_worker_pool_unittest.cc",
     "resources/resource_provider_unittest.cc",
     "resources/resource_update_controller_unittest.cc",
     "resources/scoped_resource_unittest.cc",
     "resources/task_graph_runner_unittest.cc",
     "resources/texture_mailbox_deleter_unittest.cc",
     "resources/texture_uploader_unittest.cc",
     "resources/tile_manager_unittest.cc",
     "resources/tile_priority_unittest.cc",
     "resources/video_resource_updater_unittest.cc",
+    "scheduler/begin_frame_source_unittest.cc",
     "scheduler/delay_based_time_source_unittest.cc",
     "scheduler/scheduler_state_machine_unittest.cc",
     "scheduler/scheduler_unittest.cc",
     "test/layer_tree_json_parser_unittest.cc",
     "test/test_web_graphics_context_3d_unittest.cc",
     "trees/blocking_task_runner_unittest.cc",
     "trees/damage_tracker_unittest.cc",
     "trees/layer_sorter_unittest.cc",
     "trees/layer_tree_host_common_unittest.cc",
     "trees/layer_tree_host_impl_unittest.cc",
@@ skipping 73 matching lines @@
     "//gpu/command_buffer/common:gles2_utils",
     "//media",
     "//skia",
     "//testing/gmock",
     "//testing/gtest",
     "//testing/perf",
     "//ui/gfx",
     "//ui/gfx/geometry",
   ]
 }