Add new FrameTest.* unit tests and fix discovered CefFrame-related bugs.
- Allow empty |name| argument to CefBrowser::GetFrame. This will return the main frame.
- Modify CefBrowser::GetFrame to search both assigned and unique frame names.
- Calling CefFrame::IsFocused on the main frame should return true when there are no other frames.
- Fix CefBrowser::GetFrameIdentifiers and GetFrameNames to return correct values in the renderer process (issue #1236).
- Delete NavigationTest.FrameNameIdent which is now obsoleted by the new FrameTests.

git-svn-id: http://chromiumembedded.googlecode.com/svn/trunk@1842 5089003a-bbd8-11dd-ad1f-f1f9622dbc98