Move max vibration duration constant to platform so content/ can read it.

public/platform/WebVibration.h

Index: public/platform/WebVibration.h
diff --git a/Source/core/loader/UniqueIdentifier.h b/public/platform/WebVibration.h
similarity index 88%
copy from Source/core/loader/UniqueIdentifier.h
copy to public/platform/WebVibration.h
index c1dc5a2b000338f48b787c9292d80ef1671f5600..5c61bcd3180f216bf565ca3ecb99a1ef92d4407c 100644
--- a/Source/core/loader/UniqueIdentifier.h
+++ b/public/platform/WebVibration.h
@@ -28,14 +28,14 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef UniqueIdentifier_h
-#define UniqueIdentifier_h
+#ifndef WebVibration_h
+#define WebVibration_h
 
-namespace WebCore {
+namespace WebKit {
 
-unsigned long createUniqueIdentifier();
+// Maximum duration of a vibration is 10 seconds.
+const unsigned kVibrationDurationMax = 10000;
 
-}
-
-#endif // UniqueIdentifier_h
+} // namespace WebKit
 
+#endif // WebVibration_h