Move compositor InputHandler from RenderViewImpl to RenderWidget.

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index edf102efdb5e1ec07e1072c7d14b79e42cf6c9d1..d39d30e88850b76d3117aa67942ae963ea3f7133 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -616,8 +616,24 @@ LayerTreeHostImpl::EventListenerTypeForTouchStartAt(
   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.
+    // This code can be removed once ScrollingCoordinator is per-compositor
+    // rather than per-page, https://crbug.com/680606, since a per-compositor
+    // version will correctly send touch-rects for non-mainframes.
+    EventListenerProperties properties =
+        active_tree_->event_listener_properties(
+            EventListenerClass::kTouchStartOrMove);
+    if ((properties == EventListenerProperties::kBlocking ||
+         properties == EventListenerProperties::kBlockingAndPassive) &&
+        !active_tree_->OuterViewportScrollLayer()) {
+      return InputHandler::TouchStartEventListenerType::HANDLER;
+    }
     return InputHandler::TouchStartEventListenerType::NO_HANDLER;
+  }
 
   if (!CurrentlyScrollingLayer())
     return InputHandler::TouchStartEventListenerType::HANDLER;
@@ -2995,6 +3011,7 @@ void LayerTreeHostImpl::ApplyScroll(ScrollNode* scroll_node,
   // we want to scroll the inner viewport -- to allow panning while zoomed --
   // but also move browser controls if needed.
   bool is_inner_viewport_scroll_layer =
+      InnerViewportScrollLayer() &&
       scroll_node->owning_layer_id == InnerViewportScrollLayer()->id();
 
   if (is_viewport_scroll_layer || is_inner_viewport_scroll_layer) {