Correct sRGB <-> linear everywhere.

src/effects/gradients/Sk4fLinearGradient.cpp

Index: src/effects/gradients/Sk4fLinearGradient.cpp
diff --git a/src/effects/gradients/Sk4fLinearGradient.cpp b/src/effects/gradients/Sk4fLinearGradient.cpp
index d22dbff8a170aa797e239a93582200b534eb7f38..a59a805f9f8b61bed78244e657f865a1042f24b1 100644
--- a/src/effects/gradients/Sk4fLinearGradient.cpp
+++ b/src/effects/gradients/Sk4fLinearGradient.cpp
@@ -53,13 +53,15 @@ void ramp<DstType::S32, ApplyPremul::False>(const Sk4f& c, const Sk4f& dc, SkPMC
     Sk4x4f        c4x = Sk4x4f::Transpose(c, c + dc, c + dc * 2, c + dc * 3);
 
     while (n >= 4) {
-        const Sk4x4f cx4s32 = {
-            c4x.r.rsqrt().invert(),
-            c4x.g.rsqrt().invert(),
-            c4x.b.rsqrt().invert(),
-            c4x.a
-        };
-        cx4s32.transpose((uint8_t*)dst);
+        auto r = sk_linear_to_srgb(c4x.r),
+             g = sk_linear_to_srgb(c4x.g),
+             b = sk_linear_to_srgb(c4x.b),
+             a = 255.0f *          c4x.a ;
+
+        ( Sk4f_round(r) <<  0
+        | Sk4f_round(g) <<  8
+        | Sk4f_round(b) << 16
+        | Sk4f_round(a) << 24).store(dst);
 
         c4x.r += dc4x.r;
         c4x.g += dc4x.g;