GitLab

Added back the canvas.clear() call that MSAN will whine without.

Original attempt: https://chromium-review.googlesource.com/c/chromium/src/+/919603

-------------------------Original description---------------------------

Changes the location of the RGB→Grayscale conversion of the
CopyFromSurface() result SkBitmap to be in
NavigationEntryScreenshotManager, as it is the only use case. This
unblocks a massive clean-up effort for bug 759310.

For reference, the following was the code that was doing the conversion
before (and is a part of a major chunk of code that we want to delete):
https://cs.chromium.org/chromium/src/content/browser/compositor/surface_utils.cc?rcl=2fe7073e23caa42cbd01575ab206ba8928ccd645&l=146

TBR=nick@chromium.org

Bug: 759310
Change-Id: Id859a8589c9866919ac77c4b7e18527526e38a8c
Reviewed-on: https://chromium-review.googlesource.com/922873
Commit-Queue: Yuri Wiitala <miu@chromium.org>
Reviewed-by: Yuri Wiitala <miu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537177}