For SkGPipe, store bitmaps in a common location.

Also make a change to SkBitmap::copyTo() so that we do not
crash.
Review URL: https://codereview.appspot.com/6296066

git-svn-id: http://skia.googlecode.com/svn/trunk@4249 2bbb7eff-a529-9590-31e7-b0007b416f81
3 files changed