added support for PLS path rendering

src/gpu/glsl/GrGLSLFragmentShaderBuilder.h

Index: src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
diff --git a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
index a55fdd2860ac8e548ba1a72d58a753fdadd1a8de..73e6187e3e6862680cd3a1f8fbd8f98c54ca13a4 100644
--- a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
+++ b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
@@ -33,7 +33,8 @@ public:
      */
     enum GLSLFeature {
         kStandardDerivatives_GLSLFeature = 0,
-        kLastGLSLFeature = kStandardDerivatives_GLSLFeature
+        kPixelLocalStorage_GLSLFeature = 1,
+        kLastGLSLFeature = kPixelLocalStorage_GLSLFeature
     };
 
     /**
@@ -66,6 +67,8 @@ public:
     bool hasCustomColorOutput() const { return fHasCustomColorOutput; }
     bool hasSecondaryOutput() const { return fHasSecondaryOutput; }
 
+    void declAppendf(const char* fmt, ...);
+
 protected:
     bool fHasCustomColorOutput;
     bool fHasSecondaryOutput;