Allow MimeHandlerViewGuest be embedded inside OOPIFs

content/browser/renderer_host/render_widget_host_input_event_router.cc

Index: content/browser/renderer_host/render_widget_host_input_event_router.cc
diff --git a/content/browser/renderer_host/render_widget_host_input_event_router.cc b/content/browser/renderer_host/render_widget_host_input_event_router.cc
index 3603ae2d83f8e927f3952f95a37ae7d17b8a546e..dbde911c81f5c6ec3d54789a7bdc20ebaaeb9ba4 100644
--- a/content/browser/renderer_host/render_widget_host_input_event_router.cc
+++ b/content/browser/renderer_host/render_widget_host_input_event_router.cc
@@ -197,7 +197,17 @@ void RenderWidgetHostInputEventRouter::RouteMouseEvent(
   // the embedding renderer and then BrowserPluginGuest.
   if (target && target->IsRenderWidgetHostViewGuest()) {
     ui::LatencyInfo latency_info;
-    root_view->ProcessMouseEvent(*event, latency_info);
+    RenderWidgetHostViewBase* embedder = target->GetEmbedderView();
+    if (embedder != root_view) {
+      // This happens when the view is embedded inside a cross process frame.
+      gfx::Point embedder_point;
+      if (!root_view->TransformPointToCoordSpaceForView(
+              gfx::Point(event->x, event->y), embedder, &embedder_point))
+        return;
+      event->x = embedder_point.x();
+      event->y = embedder_point.y();
+    }
+    embedder->ProcessMouseEvent(*event, latency_info);
     return;
   }