am 64dd5be5: Merge change Ia78b0a2d into eclair

Merge commit '64dd5be583bab8218e54068bbf70edc5fc6087c8' into eclair-plus-aosp

* commit '64dd5be583bab8218e54068bbf70edc5fc6087c8':
  add (hidden) setHasAlpha() to allow clients like the view's cache to hint that a bitmap is opaque.