Route touch-events for WebViewGuest directly to guest renderer.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index e01a4d5484380c82981615cd9ccd33e2f8c18092..58e6396e00b078ef443fcf3fce944adc93a03367 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1593,9 +1593,10 @@ bool WebContentsImpl::PreHandleGestureEvent(
 }
 
 RenderWidgetHostInputEventRouter* WebContentsImpl::GetInputEventRouter() {
-  // Currently only supported in site per process mode (--site-per-process).
-  if (!rwh_input_event_router_.get() && !is_being_destroyed_ &&
-      SiteIsolationPolicy::AreCrossProcessFramesPossible())
+  if (!is_being_destroyed_ && GetOuterWebContents())
+    return GetOuterWebContents()->GetInputEventRouter();

[kenrb, 2015/11/05 17:05:26]

If we create an input event router before being attached to the outer
WebContents, does that persist as an unused object containing stale
SurfaceIdNamespace/RWHV entries?

It might not be a problem, as long as we can guarantee that those entries never
get referenced, but I would worry about the potential for bugs down the road if
we are leaving around stale state like that.

[wjmaclean, 2015/11/05 17:46:16]

Yes, at present we do leave these around. I thought about deleting existing
entries before adding the new ones, but we'd had to have a way of either
remembering or retrieving the *old* InputEventROuter, which would make
GetInputEventrouter() much more complicated (though we could have a separate
function like GetLocalInputEventRouter() that wouldn't defer to the
OuterWebContents if it exists, and use it to remove things?)

At present, the input event router doesn't guarantee that its map is empty at
destruction time, so it's conceivable we could have stale state around even
outside of this CL.

Let me know if you'd like me to go the removal route ...

+
+  if (!rwh_input_event_router_.get() && !is_being_destroyed_)
     rwh_input_event_router_.reset(new RenderWidgetHostInputEventRouter);
   return rwh_input_event_router_.get();
 }