<webview>: Move name attribute to chrome

This CL introduces a new way to monitor changes to frame names from the content embedder, and setting the main frame name from the content embedder.

The name attribute is now managed by web_view.js, and not BrowserPlugin.

BUG=364141, 330264
TBR=kenrb@chromium.org (removing IPC messages).

Review URL: https://codereview.chromium.org/291483010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272241 0039d316-1c4b-4281-b951-d872f2087c98
26 files changed