Move WebInbandTextTrack/WebInbandTextTrackClient to public/platform/

public/web/WebInbandTextTrackClient.h

Index: public/web/WebInbandTextTrackClient.h
diff --git a/public/web/WebInbandTextTrackClient.h b/public/web/WebInbandTextTrackClient.h
index 42a65d2be8cc335d1c01307c1ae583b12f3c442c..8fb697fb75c2d14e5a35f65482e6f016b10b4a2f 100644
--- a/public/web/WebInbandTextTrackClient.h
+++ b/public/web/WebInbandTextTrackClient.h
@@ -28,24 +28,4 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef WebInbandTextTrackClient_h
-#define WebInbandTextTrackClient_h
-
-namespace blink {
-
-class WebString;
-
-class WebInbandTextTrackClient {
-public:
-    virtual ~WebInbandTextTrackClient() {}
-
-    virtual void addWebVTTCue(double start,
-                              double end,
-                              const WebString& id,
-                              const WebString& content,
-                              const WebString& settings) = 0;
-};
-
-} // namespace blink
-
-#endif
+#include "../platform/WebInbandTextTrackClient.h"