services/ui: Detect when a video is playing

cc/proto/layer.proto

 // 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.
 
 syntax = "proto2";
 
 import "layer_position_constraint.proto";
 import "point3f.proto";
 import "pointf.proto";
 import "recording_source.proto";
@@ skipping 49 matching lines @@
   // for their specific properties.
   optional BaseLayerProperties base = 5;
 
   // Only one of these fields may be set per LayerProperties.
   // TODO(dtrainor): use a 'oneof' union when it's supported in Chromium.  See
   // crbug.com/570371.
   optional PictureLayerProperties picture = 6;
   optional SolidColorScrollbarLayerProperties solid_scrollbar = 7;
 }
 
-// NEXT ID: 55
+// NEXT ID: 56
 message BaseLayerProperties {
   optional Point3F transform_origin = 1;
   optional uint32 background_color = 2;
   optional uint32 safe_opaque_background_color = 53;
   optional Size bounds = 3;
   optional int64 transform_free_index = 4;
   optional int64 effect_tree_index = 5;
   optional int64 clip_tree_index = 6;
   optional int64 scroll_tree_index = 50;
   optional Vector2dF offset_to_transform_parent = 7;
   optional bool double_sided = 8;
   optional bool draws_content = 9;
+  optional bool may_contain_video = 55;
   optional bool hide_layer_and_subtree = 10;
   optional bool subtree_property_changed = 47;
   optional bool layer_property_changed = 54;
   // TODO(nyquist): Add support for FilterOperation. See crbug.com/541321.
   // repeated FilterOperation filters = 12;
   // repeated FilterOperation background_filters = 13;
   optional bool masks_to_bounds = 14;
   optional uint32 main_thread_scrolling_reasons = 15;
   optional bool have_scroll_event_handlers = 17;
   optional Region non_fast_scrollable_region = 18;
@@ skipping 51 matching lines @@
     HORIZONTAL = 0;
     VERTICAL = 1;
   };
 
   optional int32 scroll_layer_id = 1;
   optional int32 thumb_thickness = 2;
   optional int32 track_start = 3;
   optional bool is_left_side_vertical_scrollbar = 4;
   optional ScrollbarOrientation orientation = 5;
 }