Fix cue rendering test and include support for left/right alignment.

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 92047be060160fb2648b8ed768a129920592262e..518de2cd725e6fc61b9bbd49d3745b9b724123a8 100644
--- a/Source/core/html/track/TextTrackCue.h
+++ b/Source/core/html/track/TextTrackCue.h
@@ -155,12 +155,13 @@ public:
 
     std::pair<double, double> getCSSPosition() const;
 
+    CSSValueID getCSSAlignment() const;
     int getCSSSize() const;
     CSSValueID getCSSWritingDirection() const;
     CSSValueID getCSSWritingMode() const;
 
     enum WritingDirection {
-        Horizontal,
+        Horizontal = 0,
         VerticalGrowingLeft,
         VerticalGrowingRight,
         NumberOfWritingDirections
@@ -168,9 +169,12 @@ public:
     WritingDirection getWritingDirection() const { return m_writingDirection; }
 
     enum CueAlignment {
-        Start,
+        Start = 0,
         Middle,
-        End
+        End,
+        Left,
+        Right,
+        NumberOfAlignments
     };
     CueAlignment getAlignment() const { return m_cueAlignment; }
 
@@ -266,9 +270,6 @@ private:
 
     CSSValueID m_displayDirection;
 
-    CSSValueID m_displayWritingModeMap[NumberOfWritingDirections];
-    CSSValueID m_displayWritingMode;
-
     int m_displaySize;
 
     std::pair<float, float> m_displayPosition;