Make SkDeferredCanvas query SkGPipeWriter for space allocated for bitmaps.

SkGPipe now has a method to report how much memory is used for its shared heap.

BUG=http://code.google.com/p/skia/issues/detail?id=738
TEST=DeferredCanvasTest

Review URL: https://codereview.appspot.com/6445046

git-svn-id: http://skia.googlecode.com/svn/trunk@4791 2bbb7eff-a529-9590-31e7-b0007b416f81
7 files changed