Support disowning window.opener across processes.

If a page sets window.opener to null, we need to ensure that all RenderViews
for that window (in any process) also disown their opener.

Also see description in spec:
http://dev.w3.org/html5/spec/single-page.html#disowned-its-opener

Note that this depends on a WebKit change to add didDisownOpener:
https://bugs.webkit.org/show_bug.cgi?id=103789

BUG=156669
TEST=Check window.opener after setting it to null and navigating cross-process.

Review URL: https://chromiumcodereview.appspot.com/11308301

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@171384 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index 8857a03..2478406 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -335,6 +335,7 @@
   virtual void DidStopLoading(RenderViewHost* render_view_host) OVERRIDE;
   virtual void DidCancelLoading() OVERRIDE;
   virtual void DidChangeLoadProgress(double progress) OVERRIDE;
+  virtual void DidDisownOpener(RenderViewHost* rvh) OVERRIDE;
   virtual void DidUpdateFrameTree(RenderViewHost* rvh) OVERRIDE;
   virtual void DocumentAvailableInMainFrame(
       RenderViewHost* render_view_host) OVERRIDE;