Use a BitmapCache for showing TabGrid screenshots

- Adds a BitmapCache to TabContentManager at size 3.2 MB
- Caches all decompressed thumbnails with url and uses that as key to
show them inside the tab grid.
- Resizes all thumbnails to half the size and square aspect ratio to
save on memory.

- Not there yet: Still passes the Bitmaps over the JNI boundary. To be
addressed at a later patch.


Change-Id: I17146258a367c4534170e0d9a2621839728b09e9
Commit-Queue: Yusuf Ozuysal <>
Reviewed-by: Matthew Jones <>
Cr-Commit-Position: refs/heads/master@{#631824}
7 files changed