added initial GLSL support to skslc

src/sksl/ir/SkSLModifiers.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 SKSL_MODIFIERS
 #define SKSL_MODIFIERS
 
 #include "../ast/SkSLASTModifiers.h"
 #include "SkSLLayout.h"
 
 namespace SkSL {
 
 /**
  * A set of modifier keywords (in, out, uniform, etc.) appearing before a declaration. 
  */
 struct Modifiers {
     enum Flag {
-        kNo_Flag      = ASTModifiers::kNo_Flag,
-        kConst_Flag   = ASTModifiers::kConst_Flag,
-        kIn_Flag      = ASTModifiers::kIn_Flag,
-        kOut_Flag     = ASTModifiers::kOut_Flag,
-        kLowp_Flag    = ASTModifiers::kLowp_Flag,
-        kMediump_Flag = ASTModifiers::kMediump_Flag,
-        kHighp_Flag   = ASTModifiers::kHighp_Flag,
-        kUniform_Flag = ASTModifiers::kUniform_Flag
+        kNo_Flag            = ASTModifiers::kNo_Flag,
+        kConst_Flag         = ASTModifiers::kConst_Flag,
+        kIn_Flag            = ASTModifiers::kIn_Flag,
+        kOut_Flag           = ASTModifiers::kOut_Flag,
+        kLowp_Flag          = ASTModifiers::kLowp_Flag,
+        kMediump_Flag       = ASTModifiers::kMediump_Flag,
+        kHighp_Flag         = ASTModifiers::kHighp_Flag,
+        kUniform_Flag       = ASTModifiers::kUniform_Flag,
+        kFlat_Flag          = ASTModifiers::kFlat_Flag,
+        kNoPerspective_Flag = ASTModifiers::kNoPerspective_Flag
     };
 
     Modifiers(const ASTModifiers& modifiers)
     : fLayout(modifiers.fLayout)
     , fFlags(modifiers.fFlags) {}
 
     Modifiers(Layout& layout, int flags)
     : fLayout(layout)
     , fFlags(flags) {}
 
     std::string description() const {
         std::string result = fLayout.description();
         if (fFlags & kUniform_Flag) {
             result += "uniform ";
         }
         if (fFlags & kConst_Flag) {
             result += "const ";
         }
         if (fFlags & kLowp_Flag) {
             result += "lowp ";
         }
         if (fFlags & kMediump_Flag) {
             result += "mediump ";
         }
         if (fFlags & kHighp_Flag) {
             result += "highp ";
         }
+        if (fFlags & kFlat_Flag) {
+            result += "flat ";
+        }
+        if (fFlags & kNoPerspective_Flag) {
+            result += "noperspective ";
+        }
 
         if ((fFlags & kIn_Flag) && (fFlags & kOut_Flag)) {
             result += "inout ";
         } else if (fFlags & kIn_Flag) {
             result += "in ";
         } else if (fFlags & kOut_Flag) {
             result += "out ";
         }
 
         return result;
     }
 
     bool operator==(const Modifiers& other) const {
         return fLayout == other.fLayout && fFlags == other.fFlags;
     }
 
     bool operator!=(const Modifiers& other) const {
         return !(*this == other);
     }
 
-    const Layout fLayout;
-    const int fFlags;
+    Layout fLayout;
+    int fFlags;
 };
 
 } // namespace
 
 #endif