Make SkGPipe use SkBitmapHeap.

In the single process (or hypothetical cross process/shared address
space) mode, SkGPipe now uses SkBitmapHeap instead of SharedHeap.

Still need to use the shared heap for shaders as well as for cross
process.

TEST=PipeTest

Review URL: https://codereview.appspot.com/6461059

git-svn-id: http://skia.googlecode.com/svn/trunk@5008 2bbb7eff-a529-9590-31e7-b0007b416f81
7 files changed