Gamma-correctness pushed into Skia, top-down.

include/core/SkSurfaceProps.h

Index: include/core/SkSurfaceProps.h
diff --git a/include/core/SkSurfaceProps.h b/include/core/SkSurfaceProps.h
index 735561f1dc9180a1cb9f044fa23856ae915f08c1..bd4fa8e7fcd60f6d224fba750a10a49bb02f316d 100644
--- a/include/core/SkSurfaceProps.h
+++ b/include/core/SkSurfaceProps.h
@@ -54,6 +54,17 @@ public:
         kDisallowAntiAlias_Flag         = 1 << 0,
         kDisallowDither_Flag            = 1 << 1,
         kUseDeviceIndependentFonts_Flag = 1 << 2,
+
+        /**
+         *  This flag causes sRGB inputs to the color pipeline (images and other sRGB-tagged
+         *  colors) to be gamma-corrected (converted to linear) before use. Without this flag,
+         *  texture scaling and filtering is not gamma correct, preserving the behavior of Skia
+         *  up through 2015.
+         *
+         *  It is recommended to enable this flag when rendering to an sRGB or floating point
+         *  surface.
+         */
+        kAllowSRGBInputs_Flag           = 1 << 3,
     };
     /** Deprecated alias used by Chromium. Will be removed. */
     static const Flags kUseDistanceFieldFonts_Flag = kUseDeviceIndependentFonts_Flag;
@@ -75,6 +86,7 @@ public:
     bool isUseDeviceIndependentFonts() const {
         return SkToBool(fFlags & kUseDeviceIndependentFonts_Flag);
     }
+    bool allowSRGBInputs() const { return SkToBool(fFlags & kAllowSRGBInputs_Flag); }
 
 private:
     SkSurfaceProps();