Null check RenderWidgetHost pointer from RWHVChildFrame on input events

content/browser/frame_host/render_widget_host_view_child_frame.cc

 // Copyright 2014 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/frame_host/render_widget_host_view_child_frame.h"
 
 #include <algorithm>
 #include <utility>
 #include <vector>
 
@@ skipping 349 matching lines @@
 
 uint32_t RenderWidgetHostViewChildFrame::GetSurfaceIdNamespace() {
   if (!use_surfaces_)
     return 0;
 
   return id_allocator_->id_namespace();
 }
 
 void RenderWidgetHostViewChildFrame::ProcessKeyboardEvent(
     const NativeWebKeyboardEvent& event) {
+  if (!host_)
+    return;
+
   host_->ForwardKeyboardEvent(event);
 }
 
 void RenderWidgetHostViewChildFrame::ProcessMouseEvent(
     const blink::WebMouseEvent& event) {
+  if (!host_)
+    return;
+
   host_->ForwardMouseEvent(event);
 }
 
 void RenderWidgetHostViewChildFrame::ProcessMouseWheelEvent(
     const blink::WebMouseWheelEvent& event) {
+  if (!host_)
+    return;
+
   if (event.deltaX != 0 || event.deltaY != 0)
     host_->ForwardWheelEvent(event);
 }
 
 gfx::Point RenderWidgetHostViewChildFrame::TransformPointToRootCoordSpace(
     const gfx::Point& point) {
   if (!frame_connector_ || !use_surfaces_)
     return point;
 
   return frame_connector_->TransformPointToRootCoordSpace(point, surface_id_);
@@ skipping 100 matching lines @@
       BrowserAccessibilityManager::GetEmptyDocument(), delegate);
 }
 
 void RenderWidgetHostViewChildFrame::ClearCompositorSurfaceIfNecessary() {
   if (surface_factory_ && !surface_id_.is_null())
     surface_factory_->Destroy(surface_id_);
   surface_id_ = cc::SurfaceId();
 }
 
 }  // namespace content