Revert of GrFP can express distance vector field req., program builder declares variable for it

src/core/SkNormalSourcePriv.h

-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SkNormalSourcePriv_DEFINED
-#define SkNormalSourcePriv_DEFINED
-
-#if SK_SUPPORT_GPU
-#include "glsl/GrGLSLFragmentProcessor.h"
-#include "glsl/GrGLSLFragmentShaderBuilder.h"
-
-/* GLSLFragmentProcessors for NormalSourceImpls must sub-class this class and override onEmitCode,
- * and setNormalData calls, as well as all other calls FPs normally override, except for the 2
- * defined in this superclass.
- * This class exists to intercept emitCode calls and emit <0, 0, 1> if the FP requires a distance
- * vector but the GP doesn't provide it. onSetData calls need to be intercepted too because
- * uniform handlers will be invalid in subclasses where onEmitCode isn't called.
- * We don't need to adjust the key here since the use of a given GP (through its class ID already in
- * the key), will determine what code gets emitted here.
- */
-class GLSLNormalFP : public GrGLSLFragmentProcessor {
-public:
-    GLSLNormalFP()
-        : fDidIntercept(false) {}
-
-    void emitCode(EmitArgs& args) final override {
-        if (args.fFp.usesDistanceVectorField() && !args.fGpImplementsDistanceVector) {
-            GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
-            fragBuilder->codeAppendf("// GLSLNormalFP intercepted emitCode call, GP does not "
-                                             "implement required distance vector feature\n");
-            fragBuilder->codeAppendf("%s = vec4(0, 0, 1, 0);", args.fOutputColor);
-
-            fDidIntercept = true;
-        } else {
-            this->onEmitCode(args);
-        }
-    }
-
-    void onSetData(const GrGLSLProgramDataManager& pdman, const GrProcessor& proc) final override {
-        if (!fDidIntercept) {
-            this->setNormalData(pdman, proc);
-        }
-    }
-
-protected:
-    virtual void onEmitCode(EmitArgs& args) = 0;
-    virtual void setNormalData(const GrGLSLProgramDataManager& pdman, const GrProcessor& proc) = 0;
-
-private:
-    bool fDidIntercept;
-};
-#endif
-
-#endif