[Mac]Implement ViewID support. (third approach)
This CL adds several extension methods to NSView class for ViewID
support, and uses a map to store ViewIDs of views.
Each view requiring ViewID support can set its ViewID upon
initialization and unset it before destruction.
When looking up a view with a specific ViewID, just search all sub views
recursively from the root view of a window.
BUG=44692 need ViewIds on mac
TEST=none
Review URL: http://codereview.chromium.org/2878037
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@53067 0039d316-1c4b-4281-b951-d872f2087c98
24 files changed
