Update layout tests to use inernals.visualViewport APIs.
This CL adds the following methods to Internals.cpp for tests that need the
visual viewport scroll position and dimensions: visualViewportHeight,
visualViewportWidth, visualViewportScrollX, visualViewportScrollY.
This is the initial CL to fix the LayoutTests that would break if the
corresponding window properties were relative to the visual viewport. This CL
branched from another CL to make shipping this window API change easier.
Original review CL: https://codereview.chromium.org/1415513002
TBR=rbyers@chromium.org
BUG=489206
Review URL: https://codereview.chromium.org/1424593002
Cr-Commit-Position: refs/heads/master@{#355926}
22 files changed
