Add ScrollDirectionPhysical enum in Scroll types.

Source/platform/scroll/ScrollTypes.h

Index: Source/platform/scroll/ScrollTypes.h
diff --git a/Source/platform/scroll/ScrollTypes.h b/Source/platform/scroll/ScrollTypes.h
index 73777d22067a16e4b2b373851c51df1b4581ef3c..1e8a51e2d114ce56f8588f29bffe1d34543e96af 100644
--- a/Source/platform/scroll/ScrollTypes.h
+++ b/Source/platform/scroll/ScrollTypes.h
@@ -42,66 +42,71 @@ enum ScrollDirection {
     ScrollInlineDirectionForward
 };
 
-inline bool isLogical(ScrollDirection direction)
-{
-    return direction >= ScrollBlockDirectionBackward;
-}
+enum ScrollDirectionPhysical {
+    ScrollPhysicalUp,

[bokan, 2015/05/21 18:54:43]

I'd make these ones ScrollUp, ScrollLeft, etc and the physical directions in the
above enum ScrollUpIgnoringWritingMode, ScrollLeftIgnoringWritingMode, etc.

+    ScrollPhysicalDown,
+    ScrollPhysicalLeft,
+    ScrollPhysicalRight,
+};
 
 // Convert logical scroll direction to physical. Physical scroll directions are unaffected.
-inline ScrollDirection toPhysicalDirection(ScrollDirection direction, bool isVertical, bool isFlipped)
+inline ScrollDirectionPhysical toPhysicalDirection(ScrollDirection direction, bool isVertical, bool isFlipped)
 {
     switch (direction) {
     case ScrollBlockDirectionBackward: {
         if (isVertical) {
             if (!isFlipped)
-                return ScrollUp;
-            return ScrollDown;
+                return ScrollPhysicalUp;
+            return ScrollPhysicalDown;
         }
         if (!isFlipped)
-            return ScrollLeft;
-        return ScrollRight;
+            return ScrollPhysicalLeft;
+        return ScrollPhysicalRight;
     }
     case ScrollBlockDirectionForward: {
         if (isVertical) {
             if (!isFlipped)
-                return ScrollDown;
-            return ScrollUp;
+                return ScrollPhysicalDown;
+            return ScrollPhysicalUp;
         }
         if (!isFlipped)
-            return ScrollRight;
-        return ScrollLeft;
+            return ScrollPhysicalRight;
+        return ScrollPhysicalLeft;
     }
     case ScrollInlineDirectionBackward: {
         if (isVertical) {
             if (!isFlipped)
-                return ScrollLeft;
-            return ScrollRight;
+                return ScrollPhysicalLeft;
+            return ScrollPhysicalRight;
         }
         if (!isFlipped)
-            return ScrollUp;
-        return ScrollDown;
+            return ScrollPhysicalUp;
+        return ScrollPhysicalDown;
     }
     case ScrollInlineDirectionForward: {
         if (isVertical) {
             if (!isFlipped)
-                return ScrollRight;
-            return ScrollLeft;
+                return ScrollPhysicalRight;
+            return ScrollPhysicalLeft;
         }
         if (!isFlipped)
-            return ScrollDown;
-        return ScrollUp;
+            return ScrollPhysicalDown;
+        return ScrollPhysicalUp;
     }
     // Direction is already physical
     case ScrollUp:
+        return ScrollPhysicalUp;
     case ScrollDown:
+        return ScrollPhysicalDown;
     case ScrollLeft:
+        return ScrollPhysicalLeft;
     case ScrollRight:
-        return direction;
+        return ScrollPhysicalRight;
     default:
         ASSERT_NOT_REACHED();
         break;
     }
-    return direction;
+    return ScrollPhysicalUp;
 }
 
 enum ScrollGranularity {