jni_generator: Pass object parameters as JavaParamRef.

chrome/browser/android/document/document_web_contents_delegate.cc

Index: chrome/browser/android/document/document_web_contents_delegate.cc
diff --git a/chrome/browser/android/document/document_web_contents_delegate.cc b/chrome/browser/android/document/document_web_contents_delegate.cc
index a56362a28a02acdc537c6a23e682fdfacc3d012c..25b8067b4bd54c8c6cee8e943c6680fa11b1caec 100644
--- a/chrome/browser/android/document/document_web_contents_delegate.cc
+++ b/chrome/browser/android/document/document_web_contents_delegate.cc
@@ -55,7 +55,6 @@ bool DocumentWebContentsDelegate::ShouldCreateWebContents(
   return false;
 }
 
-
-static jlong Initialize(JNIEnv* env, jobject obj) {
+static jlong Initialize(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   return reinterpret_cast<intptr_t>(new DocumentWebContentsDelegate(env, obj));
 }