Move download messages from Renderer to Frame filter.

third_party/WebKit/public/web/WebFrame.h

Index: third_party/WebKit/public/web/WebFrame.h
diff --git a/third_party/WebKit/public/web/WebFrame.h b/third_party/WebKit/public/web/WebFrame.h
index 5b3d907d5ffb46b048a7d4a041613c2bdcd56260..ce74a7bf941c15b548a5994c10b6e9e15df153d9 100644
--- a/third_party/WebKit/public/web/WebFrame.h
+++ b/third_party/WebKit/public/web/WebFrame.h
@@ -538,6 +538,14 @@ public:
     // Returns true if selection.anchorNode has a marker on range from |from| with |length|.
     virtual bool selectionStartHasSpellingMarkerFor(int from, int length) const = 0;
 
+    // Copy to the clipboard the image located at a particular point in visual
+    // viewport coordinates.
+    virtual void copyImageAt(const WebPoint&) = 0;

[Charlie Reis, 2016/05/13 21:50:22]

Do these need to live on WebFrame, or can they just be on WebLocalFrame?  Looks
like they're just NOTREACHED in WebRemoteFrame, and RenderFrameImpl knows it has
a WebLocalFrame.

[brettw, 2016/06/06 23:24:25]

Nothing else follows this pattern (WebLocal frame has non non-override members
it adds) so I'm hesitant to make any changes unless an expert in this API layer
asks me to change it.

[Charlie Reis, 2016/06/07 22:51:25]

I don't follow.  WebLocalFrame has lots of things that WebFrame doesn't, like
localRoot(), dispatchBeforeUnloadEvent(), loadData(), etc.  This seems to fall
in that category (i.e., things you can't do on a WebRemoteFrame). 
WebLocalFrameImpl then overrides and implements these, from one interface or the
other.

That said, I'm happy to defer to Daniel here.

[dcheng, 2016/06/08 16:00:35]

These should be on WebLocalFrame: this is consistent with the other changes
we've been making for OOPI.

[brettw, 2016/06/09 23:41:00]

Ah, when I read it I confused "= 0" with "override" and thought everything as
implemented from WebFrame! Changed.

+
+    // Save as the image located at a particular point in visual viewport
+    // coordinates.
+    virtual void saveImageAt(const WebPoint&) = 0;
+
     // Dumps the layer tree, used by the accelerated compositor, in
     // text form. This is used only by layout tests.
     virtual WebString layerTreeAsText(bool showDebugInfo = false) const = 0;