Use correct gradient calculation for rotated distance fields.

src/gpu/effects/GrDistanceFieldGeoProc.h

Index: src/gpu/effects/GrDistanceFieldGeoProc.h
diff --git a/src/gpu/effects/GrDistanceFieldGeoProc.h b/src/gpu/effects/GrDistanceFieldGeoProc.h
index 46d39f0123c6c6ee5171a99c2f4aa458d29cce37..765a531c94e8a1d89cea5911ca2655c3bfe46ded 100644
--- a/src/gpu/effects/GrDistanceFieldGeoProc.h
+++ b/src/gpu/effects/GrDistanceFieldGeoProc.h
@@ -18,7 +18,7 @@ class GrInvariantOutput;
 
 enum GrDistanceFieldEffectFlags {
     kSimilarity_DistanceFieldEffectFlag = 0x01,   // ctm is similarity matrix
-    kRectToRect_DistanceFieldEffectFlag = 0x02,   // ctm maps rects to rects
+    kScaleOnly_DistanceFieldEffectFlag  = 0x02,   // ctm has only scale and translate
     kUseLCD_DistanceFieldEffectFlag     = 0x04,   // use lcd text
     kBGR_DistanceFieldEffectFlag        = 0x08,   // lcd display has bgr order
     kPortrait_DistanceFieldEffectFlag   = 0x10,   // lcd display is in portrait mode (not used yet)
@@ -26,12 +26,13 @@ enum GrDistanceFieldEffectFlags {
     kInvalid_DistanceFieldEffectFlag    = 0x80,   // invalid state (for initialization)
     
     kUniformScale_DistanceFieldEffectMask = kSimilarity_DistanceFieldEffectFlag |
-                                            kRectToRect_DistanceFieldEffectFlag,
+                                            kScaleOnly_DistanceFieldEffectFlag,
     // The subset of the flags relevant to GrDistanceFieldA8TextGeoProc
-    kNonLCD_DistanceFieldEffectMask       = kSimilarity_DistanceFieldEffectFlag,
+    kNonLCD_DistanceFieldEffectMask       = kSimilarity_DistanceFieldEffectFlag |
+                                            kScaleOnly_DistanceFieldEffectFlag,
     // The subset of the flags relevant to GrDistanceFieldLCDTextGeoProc
     kLCD_DistanceFieldEffectMask          = kSimilarity_DistanceFieldEffectFlag |
-                                            kRectToRect_DistanceFieldEffectFlag |
+                                            kScaleOnly_DistanceFieldEffectFlag |
                                             kUseLCD_DistanceFieldEffectFlag |
                                             kBGR_DistanceFieldEffectFlag,
 };