sRGB support in Ganesh. Several pieces:

include/gpu/GrTextureParams.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrTextureParams_DEFINED
 #define GrTextureParams_DEFINED
 
 #include "GrTypes.h"
 #include "SkShader.h"
 
 /**
  * Represents the filtering and tile modes used to access a texture.
  */
 class GrTextureParams {
 public:
     static const GrTextureParams& ClampNoFilter() {
         static const GrTextureParams gParams;
         return gParams;
     }
     static const GrTextureParams& ClampBilerp() {
         static const GrTextureParams gParams(SkShader::kClamp_TileMode, kBilerp_FilterMode);
         return gParams;
     }
+    static const GrTextureParams& ClampNoFilterForceAllowSRGB() {
+        static const GrTextureParams gParams(SkShader::kClamp_TileMode, kNone_FilterMode,
+                                             kForceAllowSRGB_SRGBMode);
+        return gParams;
+    }
 
     GrTextureParams() {
         this->reset();
     }
 
     enum FilterMode {
         kNone_FilterMode,
         kBilerp_FilterMode,
         kMipMap_FilterMode
     };
 
+    enum SRGBMode {
+        kRespectDestination_SRGBMode,
+        kForceAllowSRGB_SRGBMode,
+    };
+
     GrTextureParams(SkShader::TileMode tileXAndY, FilterMode filterMode) {
         this->reset(tileXAndY, filterMode);
     }
 
+    GrTextureParams(SkShader::TileMode tileXandY, FilterMode filterMode, SRGBMode srgbMode) {
+        this->reset(tileXandY, filterMode, srgbMode);
+    }
+
     GrTextureParams(const SkShader::TileMode tileModes[2], FilterMode filterMode) {
         this->reset(tileModes, filterMode);
     }
 
     GrTextureParams(const GrTextureParams& params) {
         *this = params;
     }
 
     GrTextureParams& operator= (const GrTextureParams& params) {
         fTileModes[0] = params.fTileModes[0];
         fTileModes[1] = params.fTileModes[1];
         fFilterMode = params.fFilterMode;
+        fSRGBMode = params.fSRGBMode;
         return *this;
     }
 
     void reset() {
         this->reset(SkShader::kClamp_TileMode, kNone_FilterMode);
     }
 
     void reset(SkShader::TileMode tileXAndY, FilterMode filterMode) {
         fTileModes[0] = fTileModes[1] = tileXAndY;
         fFilterMode = filterMode;
+        fSRGBMode = kRespectDestination_SRGBMode;
+    }
+
+    void reset(SkShader::TileMode tileXandY, FilterMode filterMode, SRGBMode srgbMode) {
+        fTileModes[0] = fTileModes[1] = tileXandY;
+        fFilterMode = filterMode;
+        fSRGBMode = srgbMode;
     }
 
     void reset(const SkShader::TileMode tileModes[2], FilterMode filterMode) {
         fTileModes[0] = tileModes[0];
         fTileModes[1] = tileModes[1];
         fFilterMode = filterMode;
+        fSRGBMode = kRespectDestination_SRGBMode;
     }
 
     void setClampNoFilter() {
         fTileModes[0] = fTileModes[1] = SkShader::kClamp_TileMode;
         fFilterMode = kNone_FilterMode;
     }
 
     void setClamp() {
         fTileModes[0] = fTileModes[1] = SkShader::kClamp_TileMode;
     }
 
     void setFilterMode(FilterMode filterMode) { fFilterMode = filterMode; }
 
     void setTileModeX(const SkShader::TileMode tm) { fTileModes[0] = tm; }
     void setTileModeY(const SkShader::TileMode tm) { fTileModes[1] = tm; }
     void setTileModeXAndY(const SkShader::TileMode tm) { fTileModes[0] = fTileModes[1] = tm; }
 
+    void setSRGBMode(SRGBMode srgbMode) { fSRGBMode = srgbMode; }
+
     SkShader::TileMode getTileModeX() const { return fTileModes[0]; }
 
     SkShader::TileMode getTileModeY() const { return fTileModes[1]; }
 
     bool isTiled() const {
         return SkShader::kClamp_TileMode != fTileModes[0] ||
                SkShader::kClamp_TileMode != fTileModes[1];
     }
 
     FilterMode filterMode() const { return fFilterMode; }
 
+    SRGBMode srgbMode() const { return fSRGBMode; }
+
     bool operator== (const GrTextureParams& other) const {
         return fTileModes[0] == other.fTileModes[0] &&
                fTileModes[1] == other.fTileModes[1] &&
-               fFilterMode == other.fFilterMode;
+               fFilterMode == other.fFilterMode &&
+               fSRGBMode == other.fSRGBMode;
     }
 
     bool operator!= (const GrTextureParams& other) const { return !(*this == other); }
 
 private:
     SkShader::TileMode fTileModes[2];
     FilterMode         fFilterMode;
+    SRGBMode           fSRGBMode;
 };
 #endif