Clear last MouseMove root view in RWHIER if that view gets destroyed

content/browser/renderer_host/render_widget_host_view_base.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 259 matching lines @@
       const gfx::Point& point,
       RenderWidgetHostViewBase* target_view);
 
   // TODO(kenrb, wjmaclean): This is a temporary subclass identifier for
   // RenderWidgetHostViewGuests that is needed for special treatment during
   // input event routing. It can be removed either when RWHVGuests properly
   // support direct mouse event routing, or when RWHVGuest is removed
   // entirely, which comes first.
   virtual bool IsRenderWidgetHostViewGuest();
 
+  // Subclass identifier for RenderWidgetHostViewChildFrames. This is useful
+  // to be able to know if this RWHV is embedded within another RWHV. If
+  // other kinds of embeddable RWHVs are created, this should be renamed to
+  // a more generic term -- in which case, static casts to RWHVChildFrame will
+  // need to also be resolved.
+  virtual bool IsRenderWidgetHostViewChildFrame();
+
   //----------------------------------------------------------------------------
   // The following methods are related to IME.
   // TODO(ekaramad): Most of the IME methods should not stay virtual after IME
   // is implemented for OOPIF. After fixing IME, mark the corresponding methods
   // non-virtual (https://crbug.com/578168).
 
   // Updates the state of the input method attached to the view.
   virtual void TextInputStateChanged(const TextInputState& text_input_state);
 
   // Cancel the ongoing composition of the input method attached to the view.
@@ skipping 199 matching lines @@
   base::ObserverList<RenderWidgetHostViewBaseObserver> observers_;
 
   base::WeakPtrFactory<RenderWidgetHostViewBase> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewBase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_