The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d3706ec656557d2a8077d9a941a59be933bf8ec7

commit d3706ec656557d2a8077d9a941a59be933bf8ec7
Author: jianli <jianli@chromium.org>
Date: Fri Apr 28 23:09:24 2017

Add UMA for popup overlays removed from saved MHTML page

BUG= 715371 
TEST=tests updated

Review-Url: https://codereview.chromium.org/2841223002
Cr-Commit-Position: refs/heads/master@{#468172}

[modify] https://crrev.com/d3706ec656557d2a8077d9a941a59be933bf8ec7/third_party/WebKit/Source/core/frame/FrameSerializer.h
[modify] https://crrev.com/d3706ec656557d2a8077d9a941a59be933bf8ec7/third_party/WebKit/Source/web/WebFrameSerializer.cpp
[modify] https://crrev.com/d3706ec656557d2a8077d9a941a59be933bf8ec7/third_party/WebKit/Source/web/tests/WebFrameSerializerTest.cpp
[modify] https://crrev.com/d3706ec656557d2a8077d9a941a59be933bf8ec7/tools/metrics/histograms/histograms.xml