cc: Revert to using SkMultiPictureDraw in GpuRasterizer::RasterizeSource().

cc: Revert to using SkMultiPictureDraw in GpuRasterizer::RasterizeSource().

Using picture->playback() was causing some corrupted tiles
however it seemed fixed.  I was able to reproduce the bug on
about:tracing, so reverting back to using SkMultiPictureDraw until
fixed.

TBR=vmpstr@chromium.org
NOTRY=true
BUG=454500
Committed: https://crrev.com/be2afae76b16db4f8c85977ec3a49ae8597a94f4
Cr-Commit-Position: refs/heads/master@{#316344}

[vmiura, 2015-02-14 00:33:43]

The CQ bit was checked by vmiura@chromium.org

[commit-bot: I haz the power, 2015-02-14 00:34:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/926673003/1

[commit-bot: I haz the power, 2015-02-14 00:35:14]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-14 00:35:56]

Patchset 1 (id:??) landed as
https://crrev.com/be2afae76b16db4f8c85977ec3a49ae8597a94f4
Cr-Commit-Position: refs/heads/master@{#316344}