Make parseCompositeAndBlendOperator() take care of "normal".

Source/platform/graphics/GraphicsTypes.cpp

Index: Source/platform/graphics/GraphicsTypes.cpp
diff --git a/Source/platform/graphics/GraphicsTypes.cpp b/Source/platform/graphics/GraphicsTypes.cpp
index 2b342058f701a5546de5f43b4ddb4b759dd93564..7e5654276f2cf02a5a2256700c08b9cb8df9ca14 100644
--- a/Source/platform/graphics/GraphicsTypes.cpp
+++ b/Source/platform/graphics/GraphicsTypes.cpp
@@ -49,6 +49,7 @@ static const char* const compositeOperatorNames[] = {
 };
 
 static const char* const blendOperatorNames[] = {
+    "normal",
     "multiply",
     "screen",
     "overlay",
@@ -80,7 +81,7 @@ bool parseCompositeAndBlendOperator(const String& s, CompositeOperator& op, WebB
 
     for (int i = 0; i < numBlendOperatorNames; i++) {
         if (s == blendOperatorNames[i]) {
-            blendOp = static_cast<WebBlendMode>(i+1);
+            blendOp = static_cast<WebBlendMode>(i);
             // For now, blending will always assume source-over. This will be fixed in the future
             op = CompositeSourceOver;
             return true;