Use noperspective interpolation for 2D draws

src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp

Index: src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
diff --git a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
index 7ec18a23e814e4383fde0fcce260c20855fe8758..8651827841a103dae9f21fa598e3bf682e49556c 100644
--- a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
@@ -176,7 +176,7 @@ const char* GrGLSLFragmentShaderBuilder::dstColor() {
 
     const GrGLSLCaps* glslCaps = fProgramBuilder->glslCaps();
     if (glslCaps->fbFetchSupport()) {
-        this->addFeature(1 << (GrGLSLFragmentShaderBuilder::kLastGLSLPrivateFeature + 1),
+        this->addFeature(1 << kFramebufferFetch_GLSLPrivateFeature,
                          glslCaps->fbFetchExtensionString());
 
         // Some versions of this extension string require declaring custom color output on ES 3.0+