Vibration API: use runtime flag, change from client to platform.

public/platform/Platform.h

Index: public/platform/Platform.h
diff --git a/public/platform/Platform.h b/public/platform/Platform.h
index acff9862dc1663b4f3cc6a0b73606bc332a52457..f731cc41d941a051477db60a40a8b7b021e512d1 100644
--- a/public/platform/Platform.h
+++ b/public/platform/Platform.h
@@ -383,6 +383,16 @@ public:
     virtual long long availableDiskSpaceInBytes(const WebString& fileName) { return 0; }
 
 
+    // Vibration -----------------------------------------------------------
+
+    // Starts a vibration for the given duration in milliseconds. If there is currently an active
+    // vibration it will be cancelled before the new one is started.
+    virtual void vibrate(unsigned time) { }
+
+    // Cancels the current vibration, if there is one.
+    virtual void cancelVibration() { }
+
+
     // Testing -------------------------------------------------------------
 
 #define HAVE_WEBUNITTESTSUPPORT 1