added initial GLSL support to skslc

src/sksl/SkSLCompiler.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
  
 #include "SkSLCompiler.h"
 
 #include <fstream>
@@ skipping 205 matching lines @@
 void Compiler::writeErrorCount() {
     if (fErrorCount) {
         fErrorText += to_string(fErrorCount) + " error";
         if (fErrorCount > 1) {
             fErrorText += "s";
         }
         fErrorText += "\n";
     }
 }
 
-#include <fstream>
-bool Compiler::toSPIRV(Program::Kind kind, std::string text, std::ostream& out) {
+bool Compiler::toSPIRV(Program::Kind kind, const std::string& text, std::ostream& out) {
     auto program = this->convertProgram(kind, text);
     if (fErrorCount == 0) {
         SkSL::SPIRVCodeGenerator cg(&fContext);
         cg.generateCode(*program.get(), out);
         ASSERT(!out.rdstate());
     }
     return fErrorCount == 0;
 }
 
-bool Compiler::toSPIRV(Program::Kind kind, std::string text, std::string* out) {
+bool Compiler::toSPIRV(Program::Kind kind, const std::string& text, std::string* out) {
     std::stringstream buffer;
     bool result = this->toSPIRV(kind, text, buffer);
     if (result) {
         *out = buffer.str();
     }
+    return result;
+}
+
+bool Compiler::toGLSL(Program::Kind kind, const std::string& text, GLCaps caps, 
+                      std::ostream& out) {
+    auto program = this->convertProgram(kind, text);
+    if (fErrorCount == 0) {
+        SkSL::GLSLCodeGenerator cg(&fContext, caps);
+        cg.generateCode(*program.get(), out);
+        ASSERT(!out.rdstate());
+    }
     return fErrorCount == 0;
 }
 
+bool Compiler::toGLSL(Program::Kind kind, const std::string& text, GLCaps caps, 
+                      std::string* out) {
+    std::stringstream buffer;
+    bool result = this->toGLSL(kind, text, caps, buffer);
+    if (result) {
+        *out = buffer.str();
+    }
+    return result;
+}
+
 } // namespace