Pass JavaRef to Java methods in android_webview.

android_webview/native/aw_contents_client_bridge.cc

Index: android_webview/native/aw_contents_client_bridge.cc
diff --git a/android_webview/native/aw_contents_client_bridge.cc b/android_webview/native/aw_contents_client_bridge.cc
index c428f2421855da288ff88fe0b88b98e6f908308b..9de58888c52abdacf83285c2a0372e7486b4ae4d 100644
--- a/android_webview/native/aw_contents_client_bridge.cc
+++ b/android_webview/native/aw_contents_client_bridge.cc
@@ -52,9 +52,10 @@ void RecordClientCertificateKey(
 
 }  // namespace
 
-AwContentsClientBridge::AwContentsClientBridge(JNIEnv* env, jobject obj)
+AwContentsClientBridge::AwContentsClientBridge(JNIEnv* env,
+                                               const JavaRef<jobject>& obj)
     : java_ref_(env, obj) {
-  DCHECK(obj);
+  DCHECK(!obj.is_null());
   Java_AwContentsClientBridge_setNativeContentsClientBridge(
       env, obj, reinterpret_cast<intptr_t>(this));
 }