Split Dictionary's get and convert into DictionaryHelper.

Source/modules/mediastream/UserMediaRequest.cpp

Index: Source/modules/mediastream/UserMediaRequest.cpp
diff --git a/Source/modules/mediastream/UserMediaRequest.cpp b/Source/modules/mediastream/UserMediaRequest.cpp
index a0db4baa8f863124c5b88f4927d6859ca980a34d..a8a7657483103d4e7a7986c5a77979e2bbc32b0f 100644
--- a/Source/modules/mediastream/UserMediaRequest.cpp
+++ b/Source/modules/mediastream/UserMediaRequest.cpp
@@ -34,6 +34,7 @@
 #include "modules/mediastream/UserMediaRequest.h"
 
 #include "bindings/core/v8/Dictionary.h"
+#include "bindings/core/v8/DictionaryHelper.h"
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/Document.h"
@@ -57,7 +58,7 @@ static blink::WebMediaConstraints parseOptions(const Dictionary& options, const
         constraints = MediaConstraintsImpl::create(constraintsDictionary, exceptionState);
     else {
         bool mediaRequested = false;
-        options.get(mediaType, mediaRequested);
+        DictionaryHelper::get(options, mediaType, mediaRequested);
         if (mediaRequested)
             constraints = MediaConstraintsImpl::create();
     }