Bug 1276831 - part1 : VTTCue's position should be double or auto keyword. r=rillian,smaug

MozReview-Commit-ID: 5zsEMxbwuEH

--HG--
extra : rebase_source : 85bef3d55b06509e5178e1709a752096d0ed402a

dom/media/TextTrackCue.cpp

@@ -33,7 +33,7 @@ StaticRefPtr<nsIWebVTTParserWrapper> TextTrackCue::sParserWrapper;
 void
 TextTrackCue::SetDefaultCueSettings()
 {
-  mPosition = 50;
+  mPositionIsAutoKeyword = true;
   mPositionAlign = PositionAlignSetting::Center;
   mSize = 100.0;
   mPauseOnExit = false;
@@ -204,6 +204,20 @@ TextTrackCue::ComputedLine()
   return (-1.0) * showingTracksNum;
 }
 
+double
+TextTrackCue::ComputedPosition()
+{
+  // See spec https://w3c.github.io/webvtt/#cue-computed-position
+  if (!mPositionIsAutoKeyword) {
+    return mPosition;
+  } else if (mAlign == AlignSetting::Left) {
+    return 0.0;
+  } else if (mAlign == AlignSetting::Right) {
+    return 100.0;
+  }
+  return 50.0;
+}
+
 PositionAlignSetting
 TextTrackCue::ComputedPositionAlign()
 {

dom/media/TextTrackCue.h

@@ -190,24 +190,35 @@ public:
     mLineAlign = aLineAlign;
   }
 
-  int32_t Position() const
+  void GetPosition(OwningDoubleOrAutoKeyword& aPosition) const
   {
-    return mPosition;
-  }
-
-  void SetPosition(int32_t aPosition, ErrorResult& aRv)
-  {
-    if (mPosition == aPosition) {
+    if (mPositionIsAutoKeyword) {
+      aPosition.SetAsAutoKeyword() = AutoKeyword::Auto;
       return;
     }
+    aPosition.SetAsDouble() = mPosition;
+  }
 
-    if (aPosition > 100 || aPosition < 0){
+  void SetPosition(const DoubleOrAutoKeyword& aPosition, ErrorResult& aRv)
+  {
+    if (!aPosition.IsAutoKeyword() &&
+        (aPosition.GetAsDouble() > 100.0 || aPosition.GetAsDouble() < 0.0)){
       aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
       return;
     }
 
-    mReset = true;
-    mPosition = aPosition;
+    if (aPosition.IsDouble() &&
+        (mPositionIsAutoKeyword || (aPosition.GetAsDouble() != mPosition))) {
+      mPositionIsAutoKeyword = false;
+      mPosition = aPosition.GetAsDouble();
+      mReset = true;
+      return;
+    }
+
+    if (aPosition.IsAutoKeyword() && !mPositionIsAutoKeyword) {
+      mPositionIsAutoKeyword = true;
+      mReset = true;
+    }
   }
 
   PositionAlignSetting PositionAlign() const
@@ -300,6 +311,7 @@ public:
   }
 
   double ComputedLine();
+  double ComputedPosition();
   PositionAlignSetting ComputedPositionAlign();
 
   // Helper functions for implementation.
@@ -365,7 +377,8 @@ private:
   RefPtr<TextTrack> mTrack;
   RefPtr<HTMLTrackElement> mTrackElement;
   nsString mId;
-  int32_t mPosition;
+  double mPosition;
+  bool mPositionIsAutoKeyword;
   PositionAlignSetting mPositionAlign;
   double mSize;
   bool mPauseOnExit;

dom/webidl/VTTCue.webidl

@@ -47,7 +47,7 @@ interface VTTCue : TextTrackCue {
   [SetterThrows]
   attribute LineAlignSetting lineAlign;
   [SetterThrows]
-  attribute long position;
+  attribute (double or AutoKeyword) position;
   [SetterThrows]
   attribute PositionAlignSetting positionAlign;
   [SetterThrows]
@@ -66,5 +66,7 @@ partial interface VTTCue {
   [ChromeOnly]
   readonly attribute double computedLine;
   [ChromeOnly]
+  readonly attribute double computedPosition;
+  [ChromeOnly]
   readonly attribute PositionAlignSetting computedPositionAlign;
 };