SRGB read and write pixels working and unit test

include/gpu/GrTypes.h

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrTypes_DEFINED
 #define GrTypes_DEFINED
 
@@ skipping 295 matching lines @@
     switch (config) {
         case kRGBA_8888_GrPixelConfig:
         case kBGRA_8888_GrPixelConfig:
         case kSRGBA_8888_GrPixelConfig:
             return true;
         default:
             return false;
     }
 }
 
+// Returns true if the color (non-alpha) components represent sRGB values. It does NOT indicate that
+// all three color components are present in the config or anything about their order.
+static inline bool GrPixelConfigIsSRGB(GrPixelConfig config) {
+    switch (config) {
+        case kSRGBA_8888_GrPixelConfig:
+            return true;
+        default:
+            return false;
+    }
+}
+
 // Takes a config and returns the equivalent config with the R and B order
 // swapped if such a config exists. Otherwise, kUnknown_GrPixelConfig
 static inline GrPixelConfig GrPixelConfigSwapRAndB(GrPixelConfig config) {
     switch (config) {
         case kBGRA_8888_GrPixelConfig:
             return kRGBA_8888_GrPixelConfig;
         case kRGBA_8888_GrPixelConfig:
             return kBGRA_8888_GrPixelConfig;
         default:
             return kUnknown_GrPixelConfig;
@@ skipping 293 matching lines @@
             return 4 * width * height;
     }
 }
 
 /**
  * This value translates to reseting all the context state for any backend.
  */
 static const uint32_t kAll_GrBackendState = 0xffffffff;
 
 #endif