Bug 1186636 - Add a pref to configure -moz prefixed gradients support. r=dholbert

layout/style/nsCSSParser.cpp

@@ -58,6 +58,7 @@ typedef nsCSSProps::KTableValue KTableValue;
 // pref-backed bool values (hooked up in nsCSSParser::Startup)
 static bool sOpentypeSVGEnabled;
 static bool sUnprefixingServiceEnabled;
+static bool sMozGradientsEnabled;
 
 const uint32_t
 nsCSSProps::kParserVariantTable[eCSSProperty_COUNT_no_shorthands] = {
@@ -7416,7 +7417,8 @@ CSSParserImpl::ParseVariant(nsCSSValue& aValue,
     // a generated gradient
     nsDependentString tmp(tk->mIdent, 0);
     bool isLegacy = false;
-    if (StringBeginsWith(tmp, NS_LITERAL_STRING("-moz-"))) {
+    if (sMozGradientsEnabled &&
+        StringBeginsWith(tmp, NS_LITERAL_STRING("-moz-"))) {
       tmp.Rebind(tmp, 5);
       isLegacy = true;
     }
@@ -15675,6 +15677,8 @@ nsCSSParser::Startup()
                                "gfx.font_rendering.opentype_svg.enabled");
   Preferences::AddBoolVarCache(&sUnprefixingServiceEnabled,
                                "layout.css.unprefixing-service.enabled");
+  Preferences::AddBoolVarCache(&sMozGradientsEnabled,
+                               "layout.css.prefixes.gradients");
 }
 
 nsCSSParser::nsCSSParser(mozilla::css::Loader* aLoader,

modules/libpref/init/all.js

@@ -2259,6 +2259,7 @@ pref("layout.css.prefixes.transitions", true);
 pref("layout.css.prefixes.animations", true);
 pref("layout.css.prefixes.box-sizing", true);
 pref("layout.css.prefixes.font-features", true);
+pref("layout.css.prefixes.gradients", true);
 
 // Is the CSS Unprefixing Service enabled? (This service emulates support
 // for certain vendor-prefixed properties & values, for sites on a "fixlist".)