Add setter for GrGLSLShaderVar layout qualifier

src/gpu/glsl/GrGLSLShaderVar.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLSLShaderVar_DEFINED
 #define GrGLSLShaderVar_DEFINED
 
@@ skipping 112 matching lines @@
              const char* layoutQualifier = nullptr,
              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
         SkASSERT(kVoid_GrSLType != type);
         SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeIsFloatType(type));
         INHERITED::set(type, name, typeModifier, precision, count);
         fLayoutQualifier = layoutQualifier;
         fUseUniformFloatArrays = useUniformFloatArrays;
     }
 
     /**
+     * Set the layout qualifier
+     */
+    void setLayoutQualifier(const char* layoutQualifier) {
+        fLayoutQualifier = layoutQualifier;
+    }
+
+    /**
      * Write a declaration of this variable to out.
      */
     void appendDecl(const GrGLSLCaps* glslCaps, SkString* out) const {
         SkASSERT(kDefault_GrSLPrecision == fPrecision || GrSLTypeIsFloatType(fType));
         if (!fLayoutQualifier.isEmpty()) {
             out->appendf("layout(%s) ", fLayoutQualifier.c_str());
         }
         if (this->getTypeModifier() != kNone_TypeModifier) {
            out->append(TypeModifierString(glslCaps, this->getTypeModifier()));
            out->append(" ");
@@ skipping 79 matching lines @@
     /// Work around driver bugs on some hardware that don't correctly
     /// support uniform float []
     bool            fUseUniformFloatArrays;
 
     SkString        fLayoutQualifier;
 
     typedef GrShaderVar INHERITED;
 };
 
 #endif