Bug 1308963 - Part 3. Set initial value of mask-position as (0, 0). r=xidorn

MozReview-Commit-ID: DN7q6FrGEMA

--HG--
extra : rebase_source : 294089f79d6925d4c47202b95e270b152054f1e7

layout/style/nsCSSParser.cpp

@@ -12246,16 +12246,12 @@ CSSParserImpl::ParseImageLayersItem(
   if (eCSSProperty_mask == aTable[nsStyleImageLayers::shorthand]) {
     aState.mOrigin->mValue.SetIntValue(NS_STYLE_IMAGELAYER_ORIGIN_BORDER,
                                        eCSSUnit_Enumerated);
-
-    positionXArr->Item(1).SetPercentValue(0.5f);
-    positionYArr->Item(1).SetPercentValue(0.5f);
   } else {
     aState.mOrigin->mValue.SetIntValue(NS_STYLE_IMAGELAYER_ORIGIN_PADDING,
                                        eCSSUnit_Enumerated);
-
-    positionXArr->Item(1).SetPercentValue(0.0f);
-    positionYArr->Item(1).SetPercentValue(0.0f);
   }
+  positionXArr->Item(1).SetPercentValue(0.0f);
+  positionYArr->Item(1).SetPercentValue(0.0f);
 
   aState.mSize->mXValue.SetAutoValue();
   aState.mSize->mYValue.SetAutoValue();

layout/style/nsRuleNode.cpp

@@ -7308,9 +7308,7 @@ nsRuleNode::ComputeBackgroundData(void* aStartStruct,
 
   // background-position-x/y: enum, length, percent (flags), inherit [list]
   Position::Coord initialPositionCoord;
-  initialPositionCoord.mPercent =
-    nsStyleImageLayers::GetInitialPositionForLayerType(
-      nsStyleImageLayers::LayerType::Background);
+  initialPositionCoord.mPercent = 0.0f;
   initialPositionCoord.mLength = 0;
   initialPositionCoord.mHasPercent = true;
 
@@ -9991,9 +9989,7 @@ nsRuleNode::ComputeSVGResetData(void* aStartStruct,
 
   // mask-position-x/y: enum, length, percent (flags), inherit [list]
   Position::Coord initialPositionCoord;
-  initialPositionCoord.mPercent =
-    nsStyleImageLayers::GetInitialPositionForLayerType(
-      nsStyleImageLayers::LayerType::Mask);
+  initialPositionCoord.mPercent = 0.0f;
   initialPositionCoord.mLength = 0;
   initialPositionCoord.mHasPercent = true;
 

layout/style/nsStyleStruct.cpp

@@ -2625,11 +2625,10 @@ nsStyleImageLayers::HasLayerWithImage() const
 bool
 nsStyleImageLayers::IsInitialPositionForLayerType(Position aPosition, LayerType aType)
 {
-  float intialValue = nsStyleImageLayers::GetInitialPositionForLayerType(aType);
-  if (aPosition.mXPosition.mPercent == intialValue &&
+  if (aPosition.mXPosition.mPercent == 0.0f &&
       aPosition.mXPosition.mLength == 0 &&
       aPosition.mXPosition.mHasPercent &&
-      aPosition.mYPosition.mPercent == intialValue &&
+      aPosition.mYPosition.mPercent == 0.0f &&
       aPosition.mYPosition.mLength == 0 &&
       aPosition.mYPosition.mHasPercent) {
     return true;
@@ -2785,9 +2784,7 @@ nsStyleImageLayers::Layer::Initialize(nsStyleImageLayers::LayerType aType)
 {
   mRepeat.SetInitialValues();
 
-  float initialPositionValue =
-    nsStyleImageLayers::GetInitialPositionForLayerType(aType);
-  mPosition.SetInitialPercentValues(initialPositionValue);
+  mPosition.SetInitialPercentValues(0.0f);
 
   if (aType == LayerType::Background) {
     mOrigin = NS_STYLE_IMAGELAYER_ORIGIN_PADDING;

layout/style/nsStyleStruct.h

@@ -670,10 +670,6 @@ struct nsStyleImageLayers {
 
   static bool IsInitialPositionForLayerType(mozilla::Position aPosition, LayerType aType);
 
-  static float GetInitialPositionForLayerType(LayerType aType) {
-    return (aType == LayerType::Background) ? 0.0f : 0.5f;
-  }
-
   struct Size;
   friend struct Size;
   struct Size {