Pass JavaRef to WebContents::FromJavaWebContents.

content/browser/web_contents/web_contents_android.cc

Index: content/browser/web_contents/web_contents_android.cc
diff --git a/content/browser/web_contents/web_contents_android.cc b/content/browser/web_contents/web_contents_android.cc
index 7990f44aea19abd6557b214c8cf5671516134cde..550885a8607bf147558e6c57f3766c6f7f83c436 100644
--- a/content/browser/web_contents/web_contents_android.cc
+++ b/content/browser/web_contents/web_contents_android.cc
@@ -46,6 +46,7 @@ using base::android::ConvertJavaStringToUTF16;
 using base::android::ConvertUTF8ToJavaString;
 using base::android::ConvertUTF16ToJavaString;
 using base::android::JavaParamRef;
+using base::android::JavaRef;
 using base::android::ScopedJavaGlobalRef;
 using base::android::ScopedJavaLocalRef;
 using base::android::ToJavaIntArray;
@@ -181,9 +182,9 @@ void AXTreeSnapshotCallback(const ScopedJavaGlobalRef<jobject>& callback,
 
 // static
 WebContents* WebContents::FromJavaWebContents(
-    jobject jweb_contents_android) {
+    const JavaRef<jobject>& jweb_contents_android) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  if (!jweb_contents_android)
+  if (jweb_contents_android.is_null())
     return NULL;
 
   WebContentsAndroid* web_contents_android =