[Remoting Android] Fix GetWeakPtr() calls on multiple threads

remoting/client/jni/jni_display_handler.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 REMOTING_CLIENT_JNI_JNI_DISPLAY_HANDLER_H_
 #define REMOTING_CLIENT_JNI_JNI_DISPLAY_HANDLER_H_
 
 #include <jni.h>
 
 #include "base/android/scoped_java_ref.h"
@@ skipping 42 matching lines @@
   static bool RegisterJni(JNIEnv* env);
 
   // Schedule redraw. Can be called on any thread.
   void ScheduleRedraw(JNIEnv* env,
                       const base::android::JavaParamRef<jobject>& caller);
 
  private:
   ChromotingJniRuntime* runtime_;
 
   base::android::ScopedJavaGlobalRef<jobject> java_display_;
+  base::WeakPtr<JniDisplayHandler> weak_ptr_;
   base::WeakPtrFactory<JniDisplayHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(JniDisplayHandler);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_CLIENT_JNI_JNI_DISPLAY_HANDLER_H_