Prepare for -Wall for third-party code, -Wextra for chromium_code

base/android/context_utils.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 BASE_ANDROID_CONTEXT_UTILS_H_
 #define BASE_ANDROID_CONTEXT_UTILS_H_
 
 #include <jni.h>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/base_export.h"
 
 namespace base {
 namespace android {
 
 // Gets a global ref to the application context set with
 // InitApplicationContext(). Ownership is retained by the function - the caller
 // must NOT release it.
-const BASE_EXPORT jobject GetApplicationContext();
+BASE_EXPORT jobject GetApplicationContext();
 
 // Initialize the global application context object.
 // Either this or the Java equivalent ContextUtils.initApplicationContext must
 // be called once during startup. JNI bindings must have been initialized, as
 // the context is stored on both sides.
 BASE_EXPORT void InitApplicationContext(
     JNIEnv* env,
     const base::android::JavaRef<jobject>& context);
 
 bool RegisterContextUtils(JNIEnv* env);
 
 }  // namespace android
 }  // namespace base
 
 #endif  // BASE_ANDROID_CONTEXT_UTILS_H_