implement the logic to set tile priorities based on current matrix

cc/cc_tests.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'chromium_code': 0,
     'cc_tests_source_files': [
       'active_animation_unittest.cc',
       'content_layer_unittest.cc',
@@ skipping 34 matching lines @@
       'scheduler_state_machine_unittest.cc',
       'scheduler_unittest.cc',
       'scoped_resource_unittest.cc',
       'scrollbar_animation_controller_linear_fade_unittest.cc',
       'scrollbar_layer_unittest.cc',
       'software_renderer_unittest.cc',
       'solid_color_layer_impl_unittest.cc',
       'texture_copier_unittest.cc',
       'texture_layer_unittest.cc',
       'texture_uploader_unittest.cc',
+      'tile_priority_unittest.cc',
       'tiled_layer_impl_unittest.cc',
       'tiled_layer_unittest.cc',
       'tree_synchronizer_unittest.cc',
       'timing_function_unittest.cc',
     ],
     'cc_tests_support_files': [
       'test/animation_test_common.cc',
       'test/animation_test_common.h',
       'test/compositor_fake_web_graphics_context_3d.h',
       'test/fake_content_layer_client.cc',
@@ skipping 100 matching lines @@
           'variables': {
             'test_suite_name': 'cc_unittests',
             'input_shlib_path': '<(SHARED_LIB_DIR)/<(SHARED_LIB_PREFIX)cc_unittests<(SHARED_LIB_SUFFIX)',
           },
           'includes': [ '../build/apk_test.gypi' ],
         },
       ],
     }],
   ],
 }