[ChromeDriver] Workaround DevTools fullscreen issue

Add some workaround code while setting browser window to fullscreen
mode, to work around an issue in DevTools fullscreen command. In
particular, call document.documentElement.requestFullscreen() to ensure
that document.webkitIsFullScreen returns the correct values. All WPT
tests related to fullscreen now pass.

Also made an adjustment to WPT set_window_rect/set.py
test_fully_exit_fullscreen, which was using a width below the minimum
supported by Chrome.

Bug: 982071
Change-Id: I0e50883c3f67a566df1bc4ffd331aeac0b0ef1e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1947816
Reviewed-by: Lan Wei <lanwei@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721019}
4 files changed