Move compositor InputHandler from RenderViewImpl to RenderWidget.

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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 "cc/trees/layer_tree_host_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 592 matching lines @@
 LayerTreeHostImpl::EventListenerTypeForTouchStartAt(
     const gfx::Point& viewport_point) {
   gfx::PointF device_viewport_point = gfx::ScalePoint(
       gfx::PointF(viewport_point), active_tree_->device_scale_factor());
 
   // Now determine if there are actually any handlers at that point.
   // TODO(rbyers): Consider also honoring touch-action (crbug.com/347272).
   LayerImpl* layer_impl =
       active_tree_->FindLayerThatIsHitByPointInTouchHandlerRegion(
           device_viewport_point);
-  if (layer_impl == NULL)
+  if (layer_impl == NULL) {
+    // At present, TouchHandlerRegions are only set for LayerTrees serving the
+    // document's mainframe, i.e. LayerTrees that have a ViewPort defined. But
+    // subframes can still have touch handlers, so here we err on the side of
+    // caution and report a handler even if we don't know which layer it's on.
+    if ((active_tree_->event_listener_properties(
+             EventListenerClass::kTouchStartOrMove) ==
+         EventListenerProperties::kBlocking) &&
+        !active_tree_->OuterViewportScrollLayer()) {
+      return InputHandler::TouchStartEventListenerType::HANDLER;
+    }
     return InputHandler::TouchStartEventListenerType::NO_HANDLER;
+  }
 
   if (!CurrentlyScrollingLayer())
     return InputHandler::TouchStartEventListenerType::HANDLER;
 
   bool is_ancestor =
       IsScrolledBy(layer_impl, active_tree_->CurrentlyScrollingLayer());
   return is_ancestor ? InputHandler::TouchStartEventListenerType::
                            HANDLER_ON_SCROLLING_LAYER
                      : InputHandler::TouchStartEventListenerType::HANDLER;
 }
@@ skipping 3464 matching lines @@
       worker_context_visibility_ =
           worker_context->CacheController()->ClientBecameVisible();
     } else {
       worker_context->CacheController()->ClientBecameNotVisible(
           std::move(worker_context_visibility_));
     }
   }
 }
 
 }  // namespace cc