respect srgb gamma when building mips

src/core/SkBitmapController.h

Index: src/core/SkBitmapController.h
diff --git a/src/core/SkBitmapController.h b/src/core/SkBitmapController.h
index 86b8755ec185d4403714371d0cb4090d234d0fde..35f0c195ff6220d810b47a4b99dd01a6a3250f41 100644
--- a/src/core/SkBitmapController.h
+++ b/src/core/SkBitmapController.h
@@ -53,13 +53,18 @@ protected:
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
+#include "SkMipMap.h"
+
 class SkDefaultBitmapController : public SkBitmapController {
 public:
-    SkDefaultBitmapController() {}
+    SkDefaultBitmapController(SkMipMap::SrcGammaMode mode) : fSrcGammaMode(mode) {}
 
 protected:
     State* onRequestBitmap(const SkBitmapProvider&, const SkMatrix& inverse, SkFilterQuality,
                            void* storage, size_t storageSize) override;
+
+private:
+    const SkMipMap::SrcGammaMode fSrcGammaMode;
 };
 
 #endif