Use noperspective interpolation for 2D draws

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 e998458158af65115066d10c521afca711dd1f5b..a437a194ca2c228a61ac148b0a43aa8e6de3bc21 100644
--- a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
+++ b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
@@ -32,9 +32,8 @@ public:
      * if code is added that uses one of these features without calling enableFeature()
      */
     enum GLSLFeature {
-        kStandardDerivatives_GLSLFeature = 0,
-        kPixelLocalStorage_GLSLFeature = 1,
-        kLastGLSLFeature = kPixelLocalStorage_GLSLFeature
+        kStandardDerivatives_GLSLFeature = kLastGLSLPrivateFeature + 1,
+        kPixelLocalStorage_GLSLFeature
     };
 
     /**
@@ -168,17 +167,6 @@ private:
 
     void onFinalize() override;
 
-    /**
-     * Features that should only be enabled by GrGLSLFragmentShaderBuilder itself.
-     */
-    enum GLSLPrivateFeature {
-        kFragCoordConventions_GLSLPrivateFeature = kLastGLSLFeature + 1,
-        kBlendEquationAdvanced_GLSLPrivateFeature,
-        kBlendFuncExtended_GLSLPrivateFeature,
-        kExternalTexture_GLSLPrivateFeature,
-        kLastGLSLPrivateFeature = kBlendFuncExtended_GLSLPrivateFeature
-    };
-
     // Interpretation of FragPosKey when generating code
     enum {
         kNoFragPosRead_FragPosKey           = 0,  // The fragment positition will not be needed.