Try to fix Crash at gfx::CGImageToSkBitmap.
Try to fix Crash at gfx::CGImageToSkBitmap.

The fix is to add the check for NULL context since skia::BitmapPlatformDevice::Create might return NULL.

BUG=54880
TEST=none

Review URL: http://codereview.chromium.org/3352014

git-svn-id: http://src.chromium.org/svn/trunk/src@58952 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 0a632f3717c8caacd1094a07a48546ca9c6fdb6b
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser