Correct sRGB <-> linear everywhere.

src/core/SkColorMatrixFilterRowMajor255.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorMatrixFilterRowMajor255.h"
 #include "SkColorPriv.h"
 #include "SkNx.h"
@@ skipping 108 matching lines @@
     enum {
         R = SK_R_INDEX,
         G = SK_G_INDEX,
         B = SK_B_INDEX,
         A = SK_A_INDEX,
     };
     static SkPMColor From4f(const Sk4f& c4) {
         return round(swizzle_rb_if_bgra(c4));
     }
     static Sk4f To4f(SkPMColor c) {
-        return to_4f(c) * Sk4f(1.0f/255);
+        return Sk4f_fromL32(c);
     }
 };
 void SkColorMatrixFilterRowMajor255::filterSpan(const SkPMColor src[], int count, SkPMColor dst[]) const {
     filter_span<SkPMColorAdaptor>(fTranspose, src, count, dst);
 }
 
 struct SkPM4fAdaptor {
     enum {
         R = SkPM4f::R,
         G = SkPM4f::G,
@@ skipping 289 matching lines @@
 SkColorMatrixFilterRowMajor255::MakeSingleChannelOutput(const SkScalar row[5]) {
     SkASSERT(row);
     auto cf = sk_make_sp<SkColorMatrixFilterRowMajor255>();
     static_assert(sizeof(SkScalar) * 5 * 4 == sizeof(cf->fMatrix), "sizes don't match");
     for (int i = 0; i < 4; ++i) {
         memcpy(cf->fMatrix + 5 * i, row, sizeof(SkScalar) * 5);
     }
     cf->initState();
     return cf;
 }