Make sure bubbles in Views default to close before their RenderFrameHosts.

components/bubble/bubble_delegate.h

 // Copyright 2015 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 COMPONENTS_BUBBLE_BUBBLE_DELEGATE_H_
 #define COMPONENTS_BUBBLE_BUBBLE_DELEGATE_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "components/bubble/bubble_close_reason.h"
 
 class BubbleUi;
 
 // Inherit from this class to define a bubble. A bubble is a small transient UI
 // surface anchored to a parent window. Most bubbles are dismissed when they
 // lose focus.
 class BubbleDelegate {
  public:
   BubbleDelegate();
   virtual ~BubbleDelegate();
 
   // Called by BubbleController to notify a bubble of an event that the bubble
   // might want to close on. Return true if the bubble should close for the
-  // specified reason.
+  // specified reason. If you return false, be sure not to reference frames that
+  // are destroyed before the bubble.

[hcarmona, 2016/01/11 19:07:22]

I'm not 100% happy with this comment because it seems very specific to
BUBBLE_CLOSE_FRAME_DESTROYED. Should this warning go with that enum?
Any close reason has the potential of cleaning up data that a bubble
depends on. The onus is on the bubble to know what it can and cannot
survive.

   virtual bool ShouldClose(BubbleCloseReason reason) const;
 
   // Called by BubbleController to notify a bubble that it has closed.
   virtual void DidClose();
 
   // Called by BubbleController to build the UI that will represent this bubble.
   // BubbleDelegate should not keep a reference to this newly created UI.
   virtual scoped_ptr<BubbleUi> BuildBubbleUi() = 0;
 
   // Called to update an existing UI. This is the same BubbleUi that was created
   // in |BuildBubbleUi|.
   // Return true to indicate the UI was updated.
   virtual bool UpdateBubbleUi(BubbleUi* bubble_ui);
 
   // Used to identify a bubble for collecting metrics.
   virtual std::string GetName() const = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(BubbleDelegate);
 };
 
 #endif  // COMPONENTS_BUBBLE_BUBBLE_DELEGATE_H_