DCHECK that jstring to C++ string conversions don't pass in null.

chrome/browser/ui/android/context_menu_helper.h

 // Copyright 2013 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 CHROME_BROWSER_UI_ANDROID_CONTEXT_MENU_HELPER_H_
 #define CHROME_BROWSER_UI_ANDROID_CONTEXT_MENU_HELPER_H_
 
 #include <string>
 
 #include "base/android/jni_android.h"
@@ skipping 17 matching lines @@
 
   bool ShowContextMenu(content::RenderFrameHost* render_frame_host,
                        const content::ContextMenuParams& params);
 
   void SetPopulator(jobject jpopulator);
 
   // Methods called from Java via JNI ------------------------------------------
   void OnStartDownload(JNIEnv* env,
                        const base::android::JavaParamRef<jobject>& obj,
                        jboolean jis_link,
-                       const base::android::JavaParamRef<jstring>& jheaders);
+                       jboolean jis_data_reduction_proxy_enabled);
   void SearchForImage(JNIEnv* env,
                       const base::android::JavaParamRef<jobject>& obj);
   void ShareImage(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
 
  private:
   explicit ContextMenuHelper(content::WebContents* web_contents);
   friend class content::WebContentsUserData<ContextMenuHelper>;
 
   static base::android::ScopedJavaLocalRef<jobject> CreateJavaContextMenuParams(
       const content::ContextMenuParams& params);
 
   void OnShareImage(const std::string& thumbnail_data,
                     const gfx::Size& original_size);
 
   base::android::ScopedJavaGlobalRef<jobject> java_obj_;
   content::WebContents* web_contents_;
 
   content::ContextMenuParams context_menu_params_;
   int render_frame_id_;
   int render_process_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ContextMenuHelper);
 };
 
 bool RegisterContextMenuHelper(JNIEnv* env);
 
 #endif  // CHROME_BROWSER_UI_ANDROID_CONTEXT_MENU_HELPER_H_