cc: Add TileManager::GetActivationStateAsValue for debugging state.

cc/tiles/tile_manager.h

Index: cc/tiles/tile_manager.h
diff --git a/cc/tiles/tile_manager.h b/cc/tiles/tile_manager.h
index 5de0a15485a61a511906fa1552354f07d906643d..e410399f94391fa95a8dc86e275d63c4f721f8fd 100644
--- a/cc/tiles/tile_manager.h
+++ b/cc/tiles/tile_manager.h
@@ -229,6 +229,10 @@ class CC_EXPORT TileManager : CheckerImageTrackerClient {
   // CheckerImageTrackerClient implementation.
   void NeedsInvalidationForCheckerImagedTiles() override;
 
+  // This method can only be used for debugging information, since it performs a
+  // non trivial amount of work.
+  void GetActivationStateAsValue(base::DictionaryValue* value);

[sunnyps, 2017/04/05 21:09:50]

Can you make this return an
std::unique_ptr<base::trace_event::ConvertableToTraceFormat> here? See
Scheduler::AsValue for example. That way we can also trace this in a
disabled-by-default category.

[vmpstr, 2017/04/05 22:15:36]

Hm.. I specifically decided not to do this, since I don't think this is a
reasonable thing to trace. Maybe it's worthwhile though

+
  protected:
   friend class Tile;
   // Must be called by tile during destruction.