Clean up FrameLoader::commitProvisionalLoad

Move a couple things out to move related code, delete some duplicate logic,
and merge a couple of helpers in, since they don't have obvious divison of
responsibility.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/20556002

git-svn-id: svn://svn.chromium.org/blink/trunk@155011 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove deprecated WebTextFieldDecoratorClient API.

As soon as https://codereview.chromium.org/19597004/ lands this API will not
be needed anymore.

R=jamesr@chromium.org,esprehn@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/20560003

git-svn-id: svn://svn.chromium.org/blink/trunk@155012 bbb929c8-8fbe-4397-9dbb-9b2b20218538