Rename objects refering gfx::Rect from 'location' to 'bounds'

BUG=N/A

Review URL: https://codereview.chromium.org/80233002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236488 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236488