Enable sRGB on iOS, make sRGB decode support optional

src/gpu/gl/GrGLCaps.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef GrGLCaps_DEFINED
 #define GrGLCaps_DEFINED
@@ skipping 327 matching lines @@
     /// Are textures with GL_TEXTURE_RECTANGLE type supported.
     bool rectangleTextureSupport() const { return fRectangleTextureSupport; }
 
     /// GL_ARB_texture_swizzle
     bool textureSwizzleSupport() const { return fTextureSwizzleSupport; }
 
     bool mipMapLevelAndLodControlSupport() const { return fMipMapLevelAndLodControlSupport; }
 
     bool doManualMipmapping() const { return fDoManualMipmapping; }
 
+    bool srgbDecodeSupport() const { return fSRGBDecodeSupport; }
+
     /**
      * Returns a string containing the caps info.
      */
     SkString dump() const override;
 
     bool rgba8888PixelsOpsAreSlow() const { return fRGBA8888PixelsOpsAreSlow; }
     bool partialFBOReadIsSlow() const { return fPartialFBOReadIsSlow; }
     bool rgbaToBgraReadbackConversionsAreSlow() const {
         return fRGBAToBGRAReadbackConversionsAreSlow;
     }
@@ skipping 55 matching lines @@
     bool fIsCoreProfile : 1;
     bool fBindFragDataLocationSupport : 1;
     bool fRGBA8888PixelsOpsAreSlow : 1;
     bool fPartialFBOReadIsSlow : 1;
     bool fBindUniformLocationSupport : 1;
     bool fRectangleTextureSupport : 1;
     bool fTextureSwizzleSupport : 1;
     bool fMipMapLevelAndLodControlSupport : 1;
     bool fRGBAToBGRAReadbackConversionsAreSlow : 1;
     bool fDoManualMipmapping : 1;
+    bool fSRGBDecodeSupport : 1;
+    bool fRequireDecodeForSRGB : 1;
 
     uint32_t fBlitFramebufferFlags;
 
     /** Number type of the components (with out considering number of bits.) */
     enum FormatType {
         kNormalizedFixedPoint_FormatType,
         kFloat_FormatType,
         kInteger_FormatType,
     };
 
@@ skipping 63 matching lines @@
 
         GrSwizzle fSwizzle;
     };
 
     ConfigInfo fConfigTable[kGrPixelConfigCnt];
 
     typedef GrCaps INHERITED;
 };
 
 #endif