Fix a crash occuring during the destruction of TextInputManager on Android.

content/browser/renderer_host/text_input_manager.h

 // Copyright 2016 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_TEXT_INPUT_MANAGER_H__
 #define CONTENT_BROWSER_RENDERER_HOST_TEXT_INPUT_MANAGER_H__
 
 #include <unordered_map>
 #include <utility>
 
@@ skipping 19 matching lines @@
 class CONTENT_EXPORT TextInputManager {
  public:
   // The tab's top-level RWHV should be an observer of TextInputManager to get
   // notifications about changes in TextInputState or other IME related state
   // for child frames.
   class CONTENT_EXPORT Observer {
    public:
     // Called when a view has called UpdateTextInputState on TextInputManager.
     // If the call has led to a change in TextInputState, |did_update_state| is
     // true. In some plaforms, we need this update even when the state has not
-    // changed (e.g., Aura for updating IME).
+    // changed (e.g., Aura for updating IME). Also note that |updated_view| is
+    // the view which has most recently received an update in TextInputState.
+    // |updated_view| should not be used to obtain any IME state since this
+    // this observer method might have been called in response to unregistering

[Charlie Reis, 2016/11/30 00:05:23]

nit: this this

[EhsanK, 2016/11/30 00:34:25]

Acknowledged.

+    // the |active_view_| from TextInputManager in which case all the the |view|

[Charlie Reis, 2016/11/30 00:05:23]

nit: the the
nit: What does "all the |view| is not registered" mean?  Rephrase?

[EhsanK, 2016/11/30 00:34:25]

Thanks. I rephrased this part.

+    // is not registered anymore.
     virtual void OnUpdateTextInputStateCalled(
         TextInputManager* text_input_manager,
         RenderWidgetHostViewBase* updated_view,
         bool did_update_state) {}
     // Called when |updated_view| has called ImeCancelComposition on
     // TextInputManager.
     virtual void OnImeCancelComposition(
         TextInputManager* text_input_manager,
         RenderWidgetHostViewBase* updated_view) {}
     // Called when |updated_view| has changed its SelectionRegion.
@@ skipping 179 matching lines @@
   ViewMap<CompositionRangeInfo> composition_range_info_map_;
   ViewMap<TextSelection> text_selection_map_;
 
   base::ObserverList<Observer> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(TextInputManager);
 };
 }
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_TEXT_INPUT_MANAGER_H__