Pass method parameters as JavaParamRef in android_webview.

android_webview/native/aw_picture.h

Index: android_webview/native/aw_picture.h
diff --git a/android_webview/native/aw_picture.h b/android_webview/native/aw_picture.h
index fc4d1ec86041afccc77a926977c709072f65a6b4..bc129e5db26d73ee30c69a56b3dfda824e985360 100644
--- a/android_webview/native/aw_picture.h
+++ b/android_webview/native/aw_picture.h
@@ -23,10 +23,12 @@ class AwPicture {
   ~AwPicture();
 
   // Methods called from Java.
-  void Destroy(JNIEnv* env, jobject obj);
-  jint GetWidth(JNIEnv* env, jobject obj);
-  jint GetHeight(JNIEnv* env, jobject obj);
-  void Draw(JNIEnv* env, jobject obj, jobject canvas);
+  void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  jint GetWidth(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  jint GetHeight(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  void Draw(JNIEnv* env,
+            const base::android::JavaParamRef<jobject>& obj,
+            const base::android::JavaParamRef<jobject>& canvas);
 
  private:
   skia::RefPtr<SkPicture> picture_;