Make document.activeElement work with OOPIF

third_party/WebKit/public/web/WebLocalFrame.h

Index: third_party/WebKit/public/web/WebLocalFrame.h
diff --git a/third_party/WebKit/public/web/WebLocalFrame.h b/third_party/WebKit/public/web/WebLocalFrame.h
index dc231c9baddb1dbe2b47edcbcea96a7b56aa8d9d..89c835107460303e139664940f528796257a7ef1 100644
--- a/third_party/WebKit/public/web/WebLocalFrame.h
+++ b/third_party/WebKit/public/web/WebLocalFrame.h
@@ -152,7 +152,7 @@ public:
     // Focus ------------------------------------------------------------------
 
     // Called when this frame loses focus to a frame in another process.
-    virtual void clearFocus() = 0;
+    virtual void clearFocus(WebRemoteFrame*) = 0;

[dcheng, 2015/10/28 00:34:15]

Hm...

It feels a little wonky to have both this and WebView::setFocusedFrame. Could we
consolidate the two cleanly somehow?

[alexmos, 2015/11/02 23:23:51]

After also investigating what it'd take to support cross-process window.focus(),
I've changed the approach a little.  I removed clearFocus from WebLocalFrame,
and instead I plumb through WebView, which makes more sense anyway for
page-level FocusController stuff.

I also realized that calling setFocusedElement for this was actually not
entirely correct, as it cleared the focused element, which it didn't need to do.
 The better thing to call was FocusController::focusDocumentView, which fires
the same events without clearing the focused element in old focused frame.  This
is what I exposed from WebViewImpl.

I've changed FrameMsg_ClearFocus to FrameMsg_SetFocusedFrame, which is now sent
by the frame or proxy that needs to become focused.  So in a page A-embed-B, if
subframe B becomes focused, its proxy in A will receive this message, and we
will set the corresponding remote frame as focused in A.  This message will also
support window.focus (I've got this working in a separate CL).

 
     // Content Settings -------------------------------------------------------