Revert of Refactoring of GPU NormalMap handling out into its own class

src/core/SkLightingShader.h

Index: src/core/SkLightingShader.h
diff --git a/src/core/SkLightingShader.h b/src/core/SkLightingShader.h
index 6301eeeea13595919e5626829ac36134e93ccbe3..f25b30342a70699506cc03a5ffbc786e1e620207 100644
--- a/src/core/SkLightingShader.h
+++ b/src/core/SkLightingShader.h
@@ -16,58 +16,6 @@
 
 class SK_API SkLightingShader {
 public:
-    /** Abstract class that generates or reads in normals for use by SkLightingShader. Currently
-        implements the GPU side only. Not to be used as part of the API yet. Used internally by
-        SkLightingShader.
-    */
-    class NormalSource : public SkFlattenable {
-    public:
-        virtual ~NormalSource();
-
-#if SK_SUPPORT_GPU
-
-        /** Returns a fragment processor that takes no input and outputs a normal (already rotated)
-            as its output color. To be used as a child fragment processor.
-        */
-        virtual sk_sp<GrFragmentProcessor> asFragmentProcessor(
-                GrContext* context,
-                const SkMatrix& viewM,
-                const SkMatrix* localMatrix,
-                SkFilterQuality filterQuality,
-                SkSourceGammaTreatment gammaTreatment) const = 0;
-#endif
-
-        SK_DEFINE_FLATTENABLE_TYPE(NormalSource)
-    };
-
-    /** Returns a normal source that provides normals sourced from the the normal map argument.
-        Not to be used as part of the API yet. Used internally by SkLightingShader.
-
-        @param  normal                the normal map
-        @param  invNormRotation       rotation applied to the normal map's normals
-        @param  normLocalM            the local matrix for the normal map
-
-        nullptr will be returned if
-            'normal' is empty
-            'normal' too big (> 65535 on either side)
-
-        The normal map is currently assumed to be an 8888 image where the normal at a texel
-        is retrieved by:
-            N.x = R-127;
-            N.y = G-127;
-            N.z = B-127;
-            N.normalize();
-        The +Z axis is thus encoded in RGB as (127, 127, 255) while the -Z axis is
-        (127, 127, 0).
-    */
-    class NormalMapSource {
-    public:
-        static sk_sp<NormalSource> Make(const SkBitmap& normal, const SkVector& invNormRotation,
-                                        const SkMatrix* normLocalM);
-
-        SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
-    };
-
     /** Returns a shader that lights the diffuse and normal maps with a set of lights.
 
         It returns a shader with a reference count of 1.