Prevent browser-side hit testing when page popup is selected

content/browser/renderer_host/render_widget_host_view_event_handler.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_event_handler.h"
 
 #include "base/metrics/user_metrics_action.h"
 #include "content/browser/renderer_host/input/touch_selection_controller_client_aura.h"
 #include "content/browser/renderer_host/overscroll_controller.h"
 #include "content/browser/renderer_host/render_view_host_delegate.h"
@@ skipping 832 matching lines @@
   // 2) Touch events are always routed. In the absence of a BrowserPlugin
   //    we expect the routing to always send the event to this view. If
   //    one or more BrowserPlugins are present, then the event may be targeted
   //    to one of them, or this view. This allows GuestViews to have access to
   //    them while still forcing pinch-zoom to be handled by the top-level
   //    frame. TODO(wjmaclean): At present, this doesn't work for OOPIF, but
   //    it should be a simple extension to modify RenderWidgetHostViewChildFrame
   //    in a similar manner to RenderWidgetHostViewGuest.
   bool result = host_->delegate() && host_->delegate()->GetInputEventRouter() &&
                 !disable_input_event_router_for_testing_;
+
+  // Do not route events that are currently targeted to page popups such as
+  // <select> element drop-downs, since these cannot contain cross-process
+  // frames.
+  if (host_->delegate() && !host_->delegate()->IsWidgetForMainFrame(host_))
+    return false;
+
   // ScrollEvents get transformed into MouseWheel events, and so are treated
   // the same as mouse events for routing purposes.
   if (event->IsMouseEvent() || event->type() == ui::ET_SCROLL)
     result = result && SiteIsolationPolicy::AreCrossProcessFramesPossible();
   return result;
 }
 
 void RenderWidgetHostViewEventHandler::ProcessMouseEvent(
     const blink::WebMouseEvent& event,
     const ui::LatencyInfo& latency) {
   host_->ForwardMouseEventWithLatencyInfo(event, latency);
 }
 
 void RenderWidgetHostViewEventHandler::ProcessMouseWheelEvent(
     const blink::WebMouseWheelEvent& event,
     const ui::LatencyInfo& latency) {
   host_->ForwardWheelEventWithLatencyInfo(event, latency);
 }
 
 void RenderWidgetHostViewEventHandler::ProcessTouchEvent(
     const blink::WebTouchEvent& event,
     const ui::LatencyInfo& latency) {
   host_->ForwardTouchEventWithLatencyInfo(event, latency);
 }
 
 }  // namespace content