[UseZoomForDSF] Guest view support

content/browser/frame_host/render_widget_host_view_child_frame.cc

Index: content/browser/frame_host/render_widget_host_view_child_frame.cc
diff --git a/content/browser/frame_host/render_widget_host_view_child_frame.cc b/content/browser/frame_host/render_widget_host_view_child_frame.cc
index e8d384e723357b82d591899957195371b596131e..be4639b367df62ab9c609fa278429573951af27d 100644
--- a/content/browser/frame_host/render_widget_host_view_child_frame.cc
+++ b/content/browser/frame_host/render_widget_host_view_child_frame.cc
@@ -48,7 +48,9 @@ RenderWidgetHostViewChildFrame::RenderWidgetHostViewChildFrame(
           GetSurfaceIdNamespace(), this);
     }
   }
-
+  // Input for child frames are already scaled.
+  // TODO(oshima): This should be true for OOPIF.
+  host_->set_scale_input_to_viewport(false);

[wjmaclean, 2016/01/20 19:41:54]

If it should be true for OOPIF, can't we just do

host_->set_scale_input_to_viewport(AreCrossProcessFramesPossible() || <the new
WebView specific OOPIF flag>);

now, as opposed to later?

[oshima, 2016/01/20 21:38:49]

I looked into more, and I think we can just move this to
RenderWidgetHostViewGuest, because this is used only when scaling is necessary.
(and not used when oopif is used)

   host_->SetView(this);
 }