Disable 4 and 8 digit hex CSS colors

third_party/WebKit/Source/platform/graphics/Color.cpp

Index: third_party/WebKit/Source/platform/graphics/Color.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/Color.cpp b/third_party/WebKit/Source/platform/graphics/Color.cpp
index 15506ea9067002c0c8c563e09b1d9904b19a9fe3..39cfb207752d0d7e92121e34e654c88f9d839228 100644
--- a/third_party/WebKit/Source/platform/graphics/Color.cpp
+++ b/third_party/WebKit/Source/platform/graphics/Color.cpp
@@ -26,6 +26,7 @@
 #include "platform/graphics/Color.h"
 
 #include "platform/Decimal.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/Assertions.h"
 #include "wtf/HexNumber.h"
 #include "wtf/MathExtras.h"
@@ -121,6 +122,8 @@ static inline bool parseHexColorInternal(const CharacterType* name, unsigned len
 {
     if (length != 3 && length != 4 && length != 6 && length != 8)
         return false;
+    if ((length == 8 || length == 4) && !RuntimeEnabledFeatures::cssHexAlphaColorEnabled())
+        return false;
     unsigned value = 0;
     for (unsigned i = 0; i < length; ++i) {
         if (!isASCIIHexDigit(name[i]))