jni: Pass method parameters as JavaParamRef in content.

content/browser/android/tracing_controller_android.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 CONTENT_BROWSER_ANDROID_TRACING_CONTROLLER_ANDROID_H_
 #define CONTENT_BROWSER_ANDROID_TRACING_CONTROLLER_ANDROID_H_
 
 #include <set>
 
 #include "base/android/jni_weak_ref.h"
 #include "base/files/file_path.h"
 #include "base/memory/weak_ptr.h"
 
 namespace content {
 
 // This class implements the native methods of TracingControllerAndroid.java
 class TracingControllerAndroid {
  public:
   TracingControllerAndroid(JNIEnv* env, jobject obj);
-  void Destroy(JNIEnv* env, jobject obj);
+  void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
 
   bool StartTracing(JNIEnv* env,
-                    jobject obj,
-                    jstring categories,
-                    jstring trace_options);
-  void StopTracing(JNIEnv* env, jobject obj, jstring jfilepath);
-  bool GetKnownCategoryGroupsAsync(JNIEnv* env, jobject obj);
+                    const base::android::JavaParamRef<jobject>& obj,
+                    const base::android::JavaParamRef<jstring>& categories,
+                    const base::android::JavaParamRef<jstring>& trace_options);
+  void StopTracing(JNIEnv* env,
+                   const base::android::JavaParamRef<jobject>& obj,
+                   const base::android::JavaParamRef<jstring>& jfilepath);
+  bool GetKnownCategoryGroupsAsync(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
   static void GenerateTracingFilePath(base::FilePath* file_path);
 
  private:
   ~TracingControllerAndroid();
   void OnTracingStopped();
   void OnKnownCategoriesReceived(
       const std::set<std::string>& categories_received);
 
   JavaObjectWeakGlobalRef weak_java_object_;
   base::WeakPtrFactory<TracingControllerAndroid> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TracingControllerAndroid);
 };
 
 // Register this class's native methods through jni.
 bool RegisterTracingControllerAndroid(JNIEnv* env);
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ANDROID_TRACING_CONTROLLER_ANDROID_H_