->masonfreed for triage to see if these failures are real or just in test mode.

This CL is in review, and it fixes all popup-related layout test failures:
  https://chromium-review.googlesource.com/c/chromium/src/+/1192330

Here are the layout tests from Linux, Mac, Win with the --enable-display-compositor-pixel-dumps flag enabled:
  https://test-results.appspot.com/data/layout_results/linux-blink-rel/796/layout-test-results/results.html
  https://test-results.appspot.com/data/layout_results/mac10_13_retina-blink-rel/399/layout-test-results/results.html
  https://test-results.appspot.com/data/layout_results/win7-blink-rel/790/layout-test-results/results.html

I will close this bug once that CL lands.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e1879b6e09f4caeb6af3d2ca2c7e0da01973c316

commit e1879b6e09f4caeb6af3d2ca2c7e0da01973c316
Author: Mason Freed <masonfreed@chromium.org>
Date: Mon Sep 10 17:55:11 2018

[CI] Adding functionality to RenderWidgetHostViewAura::CopyFromSurface to capture popups.

Previous to this CL, the RenderWidgetHostViewAura::CopyFromSurface function would capture
only the main window contents. It would ignore any secondary child popup screens that
were generated as a result of many popup operations, for example calendar pickers, selection popups,
suggestion pickers, etc. With this CL, those popup screens are detected, captured, and
overlaid on top of the main window capture.

Note that in the process of implementing this, I fixed a bug in
RenderWidgetHostViewAura::GetBoundsInRootWindow(), for the Windows case. Previous to this CL,
for Windows, when legacy HWNDs are not in use (UsesNativeWindowFrame() returns false), the
function would return locations in units of DIPs divided by scale factor. It should be returning
DIPs. I moved the conversion up into the if{} block. It seems that no current test catches this
issue, but once --enable-display-compositor-pixel-dumps becomes a default flag, the existing
layout tests, under virtual/scalefactorXyz, should serve to monitor this code for regressions.

Bug:  875962 ,  667551 

Change-Id: Iefc9bfd7798b3dfabb3a28eb46009fa703c0fca0
Reviewed-on: https://chromium-review.googlesource.com/1192330
Commit-Queue: Mason Freed <masonfreed@chromium.org>
Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589975}
[modify] https://crrev.com/e1879b6e09f4caeb6af3d2ca2c7e0da01973c316/content/browser/renderer_host/delegated_frame_host.cc
[modify] https://crrev.com/e1879b6e09f4caeb6af3d2ca2c7e0da01973c316/content/browser/renderer_host/delegated_frame_host.h
[modify] https://crrev.com/e1879b6e09f4caeb6af3d2ca2c7e0da01973c316/content/browser/renderer_host/render_widget_host_view_aura.cc
[modify] https://crrev.com/e1879b6e09f4caeb6af3d2ca2c7e0da01973c316/content/browser/renderer_host/render_widget_host_view_base.cc
[modify] https://crrev.com/e1879b6e09f4caeb6af3d2ca2c7e0da01973c316/content/browser/renderer_host/render_widget_host_view_base.h
[modify] https://crrev.com/e1879b6e09f4caeb6af3d2ca2c7e0da01973c316/content/browser/renderer_host/render_widget_host_view_mac.h
[modify] https://crrev.com/e1879b6e09f4caeb6af3d2ca2c7e0da01973c316/content/browser/renderer_host/render_widget_host_view_mac.mm

CL has landed. Closing this bug.