[Chromium] Some minor cleanup in the Chromium WebKit API
There are missing WEBKIT_API decorations in WebNode.h and WebFormElement.h,
which are used to annotate methods that should be exported from WebKit.dll.
We should make WebNode::action() be a const method.
We should utilize WebFrameImpl::fromFrame() to simplify code in WebNode::frame().
Created attachment 43405 [details]
Landed as http://trac.webkit.org/changeset/51130