Revert 240915 "Revert 240681 "Revert 240536 "Mac-specific implem..."

Reason for reverting the revert of the revert (we must go deeper): Test falkiness returned after original revert was reverted.  So we have pretty strong evidence that this CL does in fact cause EventUtilsTest.TestEventFlagsFromNSEvent and EventUtilsTest.TestWindowOpenDispositionFromNSEvent to be flaky on Mac.

> Revert 240681 "Revert 240536 "Mac-specific implementation of the..."
> 
> Reverting the revert: observed failures may have been red herrings.
> 
> > Revert 240536 "Mac-specific implementation of the GlobalShortcut..."
> > 
> > Reason for revert: patch suspected of causing flakiness on
> > tests EventUtilsTest.TestEventFlagsFromNSEvent and
> > EventUtilsTest.TestWindowOpenDispositionFromNSEvent on mac10.6 and
> > mac 10.8 (ui_unit_tests on chromium.webkit waterfall)
> > 
> > > Mac-specific implementation of the GlobalShortcutListener class that
> > > listens for global shortcuts. Handles basic keyboard intercepting and
> > > forwards its output to the base class for processing.
> > > 
> > > Adds two things:
> > > 1. Intercepts media keys. Uses an event tap for intercepting media keys
> > > (PlayPause, NextTrack, PreviousTrack).
> > > 2. Binds keyboard shortcuts (hot keys). Carbon RegisterEventHotKey API for
> > > binding to non-media key global hot keys (eg. Command-Shift-1).
> > > 
> > > Also added Mac tests.
> > > 
> > > BUG=302437
> > > 
> > > Review URL: https://codereview.chromium.org/60353008
> > 
> > TBR=smus@chromium.org
> > 
> > Review URL: https://codereview.chromium.org/115323003
> 
> TBR=smus@chromium.org
> 
> Review URL: https://codereview.chromium.org/99133021

TBR=junov@chromium.org

Review URL: https://codereview.chromium.org/111643010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241044 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241044