Convert types in WebFrameLoaderClientImpl in preparation for moving

      this class into the WebKit API implementation.

R=dglazkov
BUG=10034
TEST=none

Review URL: http://codereview.chromium.org/273003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@28545 0039d316-1c4b-4281-b951-d872f2087c98