Override PreDispatchEvent() and PostDispatchEvent() in RootView
In RootView, override the EventDispatcherDelegate functions
PreDipatchEvent() and PostDispatchEvent(). This allows us to
remove the unnecessary private helper function
RootView::DispatchEventToTarget() by replacing all
of its calls with calls to
EventDispatcherDelegate::DispatchEvent() instead.
BUG=348102
TEST=none
Review URL: https://codereview.chromium.org/
176963005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256024 0039d316-1c4b-4281-b951-d872f2087c98