Observe gTreatSkColorAsSRGB for 4f gradients.

src/effects/gradients/Sk4fGradientBase.h

Index: src/effects/gradients/Sk4fGradientBase.h
diff --git a/src/effects/gradients/Sk4fGradientBase.h b/src/effects/gradients/Sk4fGradientBase.h
index ddd0b2bc466dc2bce365a54f335f2ec1fb22dea8..17f9563957aa78c453f19fbe178fa45b536df4ae 100644
--- a/src/effects/gradients/Sk4fGradientBase.h
+++ b/src/effects/gradients/Sk4fGradientBase.h
@@ -30,9 +30,8 @@ public:
 
 protected:
     struct Interval {
-        Interval(SkPMColor c0, SkScalar p0,
-                 SkPMColor c1, SkScalar p1,
-                 const Sk4f& componentScale);
+        Interval(const Sk4f& c0, SkScalar p0,
+                 const Sk4f& c1, SkScalar p1);
 
         bool isZeroRamp() const { return fZeroRamp; }