Disable CancelDragTabToWindowIn1stDisplay on ChromeOS.

This test is flaky with a real compositor, failed here:
http://build.chromium.org/p/tryserver.chromium/builders/linux_chromeos_asan/builds/12310/steps/interactive_ui_tests/logs/CancelDragTabToWindowIn1stDisplay

R=sadrul, sky
BUG=331924

Review URL: https://codereview.chromium.org/143483002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246072 0039d316-1c4b-4281-b951-d872f2087c98
Reland 246025: apps: Install the shaped window-targeter on the app windows.

Previously in chromium, a ShapedNativeAppWindowTargeter was introduced in
r245757 to make sure hit-testing for events work correctly for windows with
custom shapes. However, the targeter was never actually installed on any
window, causing it to not function properly. In this episode, we install
the shaped targeter on the window, and add a test (with some relevant
refactoring) to make sure it functions correctly.

This CL was landed in r246025, but reverted in r246031 because it broke the
clang build.

BUG=318879
R=benwells@chromium.org

Review URL: https://codereview.chromium.org/134733004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246073 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246072
SVN changes up to revision 246073