Use Promises for screen.lockOrientation().

public/platform/Platform.h

Index: public/platform/Platform.h
diff --git a/public/platform/Platform.h b/public/platform/Platform.h
index f2e79d66c03d00877a3b1b66682f1ed50092274a..11ab36e3708f5b2923c0760525fa1e038ddf5c6b 100644
--- a/public/platform/Platform.h
+++ b/public/platform/Platform.h
@@ -36,13 +36,16 @@
 #endif
 
 #include "WebAudioDevice.h"
+#include "WebCallbacks.h"
 #include "WebCommon.h"
+#include "WebDOMException.h"
 #include "WebData.h"
 #include "WebGamepadListener.h"
 #include "WebGamepads.h"
 #include "WebGraphicsContext3D.h"
 #include "WebLocalizedString.h"
 #include "WebScreenOrientationLockType.h"
+#include "WebScreenOrientationType.h"
 #include "WebSpeechSynthesizer.h"
 #include "WebStorageQuotaCallbacks.h"
 #include "WebStorageQuotaType.h"
@@ -632,8 +635,16 @@ public:
 
     // Screen Orientation -------------------------------------------------
 
+    typedef WebCallbacks<blink::WebScreenOrientationType, blink::WebDOMException> WebLockOrientationCallback;
     virtual void setScreenOrientationListener(blink::WebScreenOrientationListener*) { }
     virtual void lockOrientation(WebScreenOrientationLockType) { }
+    // Request a screen orientation lock and pass a |callback| object to be used
+    // to notify of success/failure. The |callback| parameter is expected to be
+    // owned by the implementation.
+    virtual void lockOrientation(WebScreenOrientationLockType, WebLockOrientationCallback* callback)
+    {
+        delete callback; // prevents memory leak if there is no implementation.
+    }
     virtual void unlockOrientation() { }