Initialize bitmaps to different colors, to avoid flaky success

This has been passing on devices where the readPixels is failing,
because the bitmaps sometimes start out with the same contents.

Bug: skia:
Change-Id: I4bbe2274807184720c559871e6035f436e4f6e51
Reviewed-on: https://skia-review.googlesource.com/153670
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
1 file changed