Make nsMediaFeature::mKeywordTable an mData union. (Bug 522149) r=bzbarsky

layout/style/nsCSSParser.cpp

@@ -1823,7 +1823,7 @@ CSSParserImpl::ParseMediaQueryExpression(nsMediaQuery* aQuery)
       break;
     case nsMediaFeature::eEnumerated:
       rv = ParseVariant(expr->mValue, VARIANT_KEYWORD,
-                        feature->mKeywordTable);
+                        feature->mData.mKeywordTable);
       break;
   }
   if (!rv || !ExpectSymbol(')', PR_TRUE)) {

layout/style/nsCSSStyleSheet.cpp

@@ -462,7 +462,7 @@ nsMediaQuery::AppendToString(nsAString& aString) const
                        "bad unit");
           AppendASCIItoUTF16(
               nsCSSProps::ValueToKeyword(expr.mValue.GetIntValue(),
-                                         feature->mKeywordTable),
+                                         feature->mData.mKeywordTable),
               aString);
           break;
       }

layout/style/nsMediaFeatures.cpp

@@ -262,91 +262,91 @@ nsMediaFeatures::features[] = {
         &nsGkAtoms::width,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eLength,
-        nsnull,
+        { nsnull },
         GetWidth
     },
     {
         &nsGkAtoms::height,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eLength,
-        nsnull,
+        { nsnull },
         GetHeight
     },
     {
         &nsGkAtoms::deviceWidth,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eLength,
-        nsnull,
+        { nsnull },
         GetDeviceWidth
     },
     {
         &nsGkAtoms::deviceHeight,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eLength,
-        nsnull,
+        { nsnull },
         GetDeviceHeight
     },
     {
         &nsGkAtoms::orientation,
         nsMediaFeature::eMinMaxNotAllowed,
         nsMediaFeature::eEnumerated,
-        kOrientationKeywords,
+        { kOrientationKeywords },
         GetOrientation
     },
     {
         &nsGkAtoms::aspectRatio,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eIntRatio,
-        nsnull,
+        { nsnull },
         GetAspectRatio
     },
     {
         &nsGkAtoms::deviceAspectRatio,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eIntRatio,
-        nsnull,
+        { nsnull },
         GetDeviceAspectRatio
     },
     {
         &nsGkAtoms::color,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eInteger,
-        nsnull,
+        { nsnull },
         GetColor
     },
     {
         &nsGkAtoms::colorIndex,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eInteger,
-        nsnull,
+        { nsnull },
         GetColorIndex
     },
     {
         &nsGkAtoms::monochrome,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eInteger,
-        nsnull,
+        { nsnull },
         GetMonochrome
     },
     {
         &nsGkAtoms::resolution,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eResolution,
-        nsnull,
+        { nsnull },
         GetResolution
     },
     {
         &nsGkAtoms::scan,
         nsMediaFeature::eMinMaxNotAllowed,
         nsMediaFeature::eEnumerated,
-        kScanKeywords,
+        { kScanKeywords },
         GetScan
     },
     {
         &nsGkAtoms::grid,
         nsMediaFeature::eMinMaxNotAllowed,
         nsMediaFeature::eBoolInteger,
-        nsnull,
+        { nsnull },
         GetGrid
     },
     // Null-mName terminator:
@@ -354,7 +354,7 @@ nsMediaFeatures::features[] = {
         nsnull,
         nsMediaFeature::eMinMaxAllowed,
         nsMediaFeature::eInteger,
-        nsnull,
+        { nsnull },
         nsnull
     },
 };

layout/style/nsMediaFeatures.h

@@ -73,8 +73,15 @@ struct nsMediaFeature {
     };
     ValueType mValueType;
 
-    // The same format as the keyword tables in nsCSSProps.
-    const PRInt32* mKeywordTable;
+    union {
+      // In static arrays, it's the first member that's initialized.  We
+      // need that to be void* so we can initialize both other types.
+      // This member should never be accessed by name.
+      const void* mInitializer_;
+      // If mValueType == eEnumerated:  const PRInt32*: keyword table in
+      //   the same format as the keyword tables in nsCSSProps.
+      const PRInt32* mKeywordTable;
+    } mData;
 
     // A function that returns the current value for this feature for a
     // given presentation.  If it returns eCSSUnit_Null, the feature is