Tweak the TextTrackCue "cue index" management

Source/core/html/track/TextTrackCue.h

Index: Source/core/html/track/TextTrackCue.h
diff --git a/Source/core/html/track/TextTrackCue.h b/Source/core/html/track/TextTrackCue.h
index 398a965d2b04ea0186d290b5e937d228f14eb782..48c334af01a7893e56a33ec880db2d8bc128f0dc 100644
--- a/Source/core/html/track/TextTrackCue.h
+++ b/Source/core/html/track/TextTrackCue.h
@@ -70,8 +70,8 @@ public:
     bool pauseOnExit() const { return m_pauseOnExit; }
     void setPauseOnExit(bool);
 
-    int cueIndex();
-    void invalidateCueIndex();
+    unsigned cueIndex();

[philipj_slow, 2015/02/26 15:43:12]

I'm not sure if Blink or Chromium has an exception, but the Google C++ Style
Guide does not approve:
http://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Integer_Types

I think size_t would be allowed, even though it's also unsigned.

[fs, 2015/02/26 16:09:34]

Blink most certainly is excepted (to not just say "different"). I can use
uint32_t here though if you like. Don't want to blow it up to size_t now that I
managed to pack so neatly with the bitfield... ;-)

+    void updateCueIndex(unsigned cueIndex) { m_cueIndex = cueIndex; }
 
     using EventTarget::dispatchEvent;
     virtual bool dispatchEvent(PassRefPtrWillBeRawPtr<Event>) override;
@@ -112,10 +112,11 @@ private:
     AtomicString m_id;
     double m_startTime;
     double m_endTime;
-    int m_cueIndex;
 
     RawPtrWillBeMember<TextTrack> m_track;
 
+    unsigned m_cueIndex;
+
     bool m_isActive : 1;
     bool m_pauseOnExit : 1;
 };