The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a493e977da564efbe6012947f9342d7471c4103e

commit a493e977da564efbe6012947f9342d7471c4103e
Author: Reza.Zakerinasab <zakerinasab@chromium.org>
Date: Sat Aug 26 02:15:24 2017

Fix SRGB color correction tolerance in CRC2D color correction unit test

This change sets the color correction tolerance for SRGB canvas in
putImageData/getImageData turnaround test to 1 (previously 5).
After digging it seems that the higher error in this test was due
to unpremul->premul->unpremul conversion error in clamped uint8.
To fix this, one of the alpha values of the test data is increased
and some additional minor corrections are applied.

Bug:  755668 
Change-Id: Ifb0c55531e151ae93e775da9de3dbfcec5e271fe
Reviewed-on: https://chromium-review.googlesource.com/635403
Reviewed-by: Xida Chen <xidachen@chromium.org>
Reviewed-by: Justin Novosad <junov@chromium.org>
Commit-Queue: Mohammad Reza Zakerinasab <zakerinasab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#497636}
[modify] https://crrev.com/a493e977da564efbe6012947f9342d7471c4103e/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DTest.cpp