Shared surface texture

Shared surface texture

Instead of assigning each tile a Surface Texture, now just a normal GL texture.
The content from skia bitmap will first drawn into a queue of Surface Textures,
at draw time, blit them into each tile's GL texture.
Added extra lock to protect the queue operation and Surface Texture operation.

bug:5044597

Change-Id: I25f46228b93a3e99526daf52d8bd0d8d8fcc2879