re-land of switched skslc from std::string to SkString

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=5084

Change-Id: Ib21c30afc0d8483392b417e660b7fecfcc30e617
Reviewed-on: https://skia-review.googlesource.com/5084
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>

34 files changed, 84 insertions, 87 deletions

diff --git a/src/sksl/ast/SkSLASTBinaryExpression.h b/src/sksl/ast/SkSLASTBinaryExpression.h
index 88feba66a7..c4b6e3a45b 100644
--- a/src/sksl/ast/SkSLASTBinaryExpression.h
+++ b/src/sksl/ast/SkSLASTBinaryExpression.h
@@ -10,7 +10,6 @@
 
 #include "SkSLASTExpression.h"
 #include "../SkSLToken.h"
-#include <sstream>
 
 namespace SkSL {
 
@@ -25,7 +24,7 @@ struct ASTBinaryExpression : public ASTExpression {
     , fOperator(op.fKind)
     , fRight(std::move(right)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return "(" + fLeft->description() + " " + Token::OperatorName(fOperator) + " " +
                fRight->description() + ")";
     }
diff --git a/src/sksl/ast/SkSLASTBlock.h b/src/sksl/ast/SkSLASTBlock.h
index 09450a3db8..6b1e9c5551 100644
--- a/src/sksl/ast/SkSLASTBlock.h
+++ b/src/sksl/ast/SkSLASTBlock.h
@@ -20,8 +20,8 @@ struct ASTBlock : public ASTStatement {
     : INHERITED(position, kBlock_Kind)
     , fStatements(std::move(statements)) {}
 
-    std::string description() const override {
-        std::string result("{");
+    SkString description() const override {
+        SkString result("{");
         for (size_t i = 0; i < fStatements.size(); i++) {
             result += "\n";
             result += fStatements[i]->description();
diff --git a/src/sksl/ast/SkSLASTBoolLiteral.h b/src/sksl/ast/SkSLASTBoolLiteral.h
index ff58822952..02f4bac0da 100644
--- a/src/sksl/ast/SkSLASTBoolLiteral.h
+++ b/src/sksl/ast/SkSLASTBoolLiteral.h
@@ -20,8 +20,8 @@ struct ASTBoolLiteral : public ASTExpression {
     : INHERITED(position, kBool_Kind)
     , fValue(value) {}
 
-    std::string description() const override {
-        return fValue ? "true" : "false";
+    SkString description() const override {
+        return SkString(fValue ? "true" : "false");
     }
 
     const bool fValue;
diff --git a/src/sksl/ast/SkSLASTBreakStatement.h b/src/sksl/ast/SkSLASTBreakStatement.h
index ede548cc24..dad2a85c0a 100644
--- a/src/sksl/ast/SkSLASTBreakStatement.h
+++ b/src/sksl/ast/SkSLASTBreakStatement.h
@@ -19,8 +19,8 @@ struct ASTBreakStatement : public ASTStatement {
     ASTBreakStatement(Position position)
     : INHERITED(position, kBreak_Kind) {}
 
-    std::string description() const override {
-        return "break;";
+    SkString description() const override {
+        return SkString("break;");
     }
 
     typedef ASTStatement INHERITED;
diff --git a/src/sksl/ast/SkSLASTCallSuffix.h b/src/sksl/ast/SkSLASTCallSuffix.h
index 5cff6f6c93..356ac850f9 100644
--- a/src/sksl/ast/SkSLASTCallSuffix.h
+++ b/src/sksl/ast/SkSLASTCallSuffix.h
@@ -8,7 +8,6 @@
 #ifndef SKSL_ASTCALLSUFFIX
 #define SKSL_ASTCALLSUFFIX
 
-#include <sstream>
 #include <vector>
 #include "SkSLASTSuffix.h"
 
@@ -22,9 +21,9 @@ struct ASTCallSuffix : public ASTSuffix {
     : INHERITED(position, ASTSuffix::kCall_Kind)
     , fArguments(std::move(arguments)) {}
 
-    std::string description() const override {
-        std::string result("(");
-        std::string separator = "";
+    SkString description() const override {
+        SkString result("(");
+        SkString separator;
         for (size_t i = 0; i < fArguments.size(); ++i) {
             result += separator;
             separator = ", ";
diff --git a/src/sksl/ast/SkSLASTContinueStatement.h b/src/sksl/ast/SkSLASTContinueStatement.h
index d5ab7a5c74..4cded3b16b 100644
--- a/src/sksl/ast/SkSLASTContinueStatement.h
+++ b/src/sksl/ast/SkSLASTContinueStatement.h
@@ -19,8 +19,8 @@ struct ASTContinueStatement : public ASTStatement {
     ASTContinueStatement(Position position)
     : INHERITED(position, kContinue_Kind) {}
 
-    std::string description() const override {
-        return "continue;";
+    SkString description() const override {
+        return SkString("continue;");
     }
 
     typedef ASTStatement INHERITED;
diff --git a/src/sksl/ast/SkSLASTDiscardStatement.h b/src/sksl/ast/SkSLASTDiscardStatement.h
index 4eaeec9ea4..754bf95efe 100644
--- a/src/sksl/ast/SkSLASTDiscardStatement.h
+++ b/src/sksl/ast/SkSLASTDiscardStatement.h
@@ -19,8 +19,8 @@ struct ASTDiscardStatement : public ASTStatement {
     ASTDiscardStatement(Position position)
     : INHERITED(position, kDiscard_Kind) {}
 
-    std::string description() const override {
-        return "discard;";
+    SkString description() const override {
+        return SkString("discard;");
     }
 
     typedef ASTStatement INHERITED;
diff --git a/src/sksl/ast/SkSLASTDoStatement.h b/src/sksl/ast/SkSLASTDoStatement.h
index a952d62eb5..9a0caced1c 100644
--- a/src/sksl/ast/SkSLASTDoStatement.h
+++ b/src/sksl/ast/SkSLASTDoStatement.h
@@ -22,7 +22,7 @@ struct ASTDoStatement : public ASTStatement {
     , fStatement(std::move(statement))
     , fTest(std::move(test)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return "do " + fStatement->description() + " while (" + fTest->description() + ");";
     }
 
diff --git a/src/sksl/ast/SkSLASTExpressionStatement.h b/src/sksl/ast/SkSLASTExpressionStatement.h
index 450cca29fc..2dbd20940d 100644
--- a/src/sksl/ast/SkSLASTExpressionStatement.h
+++ b/src/sksl/ast/SkSLASTExpressionStatement.h
@@ -20,7 +20,7 @@ struct ASTExpressionStatement : public ASTStatement {
     : INHERITED(expression->fPosition, kExpression_Kind)
     , fExpression(std::move(expression)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return fExpression->description() + ";";
     }
 
diff --git a/src/sksl/ast/SkSLASTExtension.h b/src/sksl/ast/SkSLASTExtension.h
index 896ac46c58..b9df3c52e9 100644
--- a/src/sksl/ast/SkSLASTExtension.h
+++ b/src/sksl/ast/SkSLASTExtension.h
@@ -16,15 +16,15 @@ namespace SkSL {
  * An extension declaration. 
  */
 struct ASTExtension : public ASTDeclaration {
-    ASTExtension(Position position, std::string name)
+    ASTExtension(Position position, SkString name)
     : INHERITED(position, kExtension_Kind)
     , fName(std::move(name)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return "#extension " + fName + " : enable";
     }
 
-    const std::string fName;
+    const SkString fName;
 
     typedef ASTDeclaration INHERITED;
 };
diff --git a/src/sksl/ast/SkSLASTFieldSuffix.h b/src/sksl/ast/SkSLASTFieldSuffix.h
index cf141d822f..9ee8531bf1 100644
--- a/src/sksl/ast/SkSLASTFieldSuffix.h
+++ b/src/sksl/ast/SkSLASTFieldSuffix.h
@@ -17,15 +17,15 @@ namespace SkSL {
  * actually vector swizzle (which looks the same to the parser).
  */
 struct ASTFieldSuffix : public ASTSuffix {
-    ASTFieldSuffix(Position position, std::string field) 
+    ASTFieldSuffix(Position position, SkString field) 
     : INHERITED(position, ASTSuffix::kField_Kind)
     , fField(std::move(field)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return "." + fField;
     }
 
-    std::string fField;
+    SkString fField;
 
     typedef ASTSuffix INHERITED;
 };
diff --git a/src/sksl/ast/SkSLASTFloatLiteral.h b/src/sksl/ast/SkSLASTFloatLiteral.h
index 89d43cc003..ea0f595abc 100644
--- a/src/sksl/ast/SkSLASTFloatLiteral.h
+++ b/src/sksl/ast/SkSLASTFloatLiteral.h
@@ -20,7 +20,7 @@ struct ASTFloatLiteral : public ASTExpression {
     : INHERITED(position, kFloat_Kind)
     , fValue(value) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return to_string(fValue);
     }
 
diff --git a/src/sksl/ast/SkSLASTForStatement.h b/src/sksl/ast/SkSLASTForStatement.h
index f4f68c8f40..2706a39954 100644
--- a/src/sksl/ast/SkSLASTForStatement.h
+++ b/src/sksl/ast/SkSLASTForStatement.h
@@ -25,8 +25,8 @@ struct ASTForStatement : public ASTStatement {
     , fNext(std::move(next))
     , fStatement(std::move(statement)) {}
 
-    std::string description() const override {
-        std::string result = "for (";
+    SkString description() const override {
+        SkString result("for (");
         if (fInitializer) {
             result.append(fInitializer->description());
         }
diff --git a/src/sksl/ast/SkSLASTFunction.h b/src/sksl/ast/SkSLASTFunction.h
index c5c3b9ad83..32f4da71f2 100644
--- a/src/sksl/ast/SkSLASTFunction.h
+++ b/src/sksl/ast/SkSLASTFunction.h
@@ -19,7 +19,7 @@ namespace SkSL {
  * A function declaration or definition. The fBody field will be null for declarations. 
  */
 struct ASTFunction : public ASTDeclaration {
-    ASTFunction(Position position, std::unique_ptr<ASTType> returnType, std::string name,
+    ASTFunction(Position position, std::unique_ptr<ASTType> returnType, SkString name,
                 std::vector<std::unique_ptr<ASTParameter>> parameters, 
                 std::unique_ptr<ASTBlock> body)
     : INHERITED(position, kFunction_Kind)
@@ -28,8 +28,8 @@ struct ASTFunction : public ASTDeclaration {
     , fParameters(std::move(parameters))
     , fBody(std::move(body)) {}
 
-    std::string description() const override {
-        std::string result = fReturnType->description() + " " + fName + "(";
+    SkString description() const override {
+        SkString result = fReturnType->description() + " " + fName + "(";
         for (size_t i = 0; i < fParameters.size(); i++) {
             if (i > 0) {
                 result += ", ";
@@ -45,7 +45,7 @@ struct ASTFunction : public ASTDeclaration {
     }
 
     const std::unique_ptr<ASTType> fReturnType;
-    const std::string fName;
+    const SkString fName;
     const std::vector<std::unique_ptr<ASTParameter>> fParameters;
     const std::unique_ptr<ASTBlock> fBody;
 
diff --git a/src/sksl/ast/SkSLASTIdentifier.h b/src/sksl/ast/SkSLASTIdentifier.h
index d67f64d39b..aa0179a18f 100644
--- a/src/sksl/ast/SkSLASTIdentifier.h
+++ b/src/sksl/ast/SkSLASTIdentifier.h
@@ -16,15 +16,15 @@ namespace SkSL {
  * An identifier in an expression context. 
  */
 struct ASTIdentifier : public ASTExpression {
-    ASTIdentifier(Position position, std::string text)
+    ASTIdentifier(Position position, SkString text)
     : INHERITED(position, kIdentifier_Kind)
     , fText(std::move(text)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return fText;
     }
 
-    const std::string fText;
+    const SkString fText;
 
     typedef ASTExpression INHERITED;
 };
diff --git a/src/sksl/ast/SkSLASTIfStatement.h b/src/sksl/ast/SkSLASTIfStatement.h
index 06f663d5fb..d169702710 100644
--- a/src/sksl/ast/SkSLASTIfStatement.h
+++ b/src/sksl/ast/SkSLASTIfStatement.h
@@ -23,8 +23,8 @@ struct ASTIfStatement : public ASTStatement {
     , fIfTrue(std::move(ifTrue))
     , fIfFalse(std::move(ifFalse)) {}
 
-    std::string description() const override {
-        std::string result("if (");
+    SkString description() const override {
+        SkString result("if (");
         result += fTest->description();
         result += ") ";
         result += fIfTrue->description();
diff --git a/src/sksl/ast/SkSLASTIndexSuffix.h b/src/sksl/ast/SkSLASTIndexSuffix.h
index 755029b0a2..2b7cd48417 100644
--- a/src/sksl/ast/SkSLASTIndexSuffix.h
+++ b/src/sksl/ast/SkSLASTIndexSuffix.h
@@ -26,11 +26,11 @@ struct ASTIndexSuffix : public ASTSuffix {
     : INHERITED(expression ? expression->fPosition : Position(), ASTSuffix::kIndex_Kind)
     , fExpression(std::move(expression)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         if (fExpression) {
             return "[" + fExpression->description() + "]";
         } else {
-            return "[]";
+            return SkString("[]");
         }
     }
 
diff --git a/src/sksl/ast/SkSLASTIntLiteral.h b/src/sksl/ast/SkSLASTIntLiteral.h
index 2598847534..f524bc04ad 100644
--- a/src/sksl/ast/SkSLASTIntLiteral.h
+++ b/src/sksl/ast/SkSLASTIntLiteral.h
@@ -21,7 +21,7 @@ struct ASTIntLiteral : public ASTExpression {
     : INHERITED(position, kInt_Kind)
     , fValue(value) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return to_string(fValue);
     }
 
diff --git a/src/sksl/ast/SkSLASTInterfaceBlock.h b/src/sksl/ast/SkSLASTInterfaceBlock.h
index c271362071..8d86c7c4f1 100644
--- a/src/sksl/ast/SkSLASTInterfaceBlock.h
+++ b/src/sksl/ast/SkSLASTInterfaceBlock.h
@@ -24,8 +24,8 @@ struct ASTInterfaceBlock : public ASTDeclaration {
     // valueName is empty when it was not present in the source
     ASTInterfaceBlock(Position position,
                       ASTModifiers modifiers, 
-                      std::string interfaceName, 
-                      std::string valueName, 
+                      SkString interfaceName, 
+                      SkString valueName, 
                       std::vector<std::unique_ptr<ASTVarDeclarations>> declarations)
     : INHERITED(position, kInterfaceBlock_Kind)
     , fModifiers(modifiers)
@@ -33,21 +33,21 @@ struct ASTInterfaceBlock : public ASTDeclaration {
     , fValueName(std::move(valueName))
     , fDeclarations(std::move(declarations)) {}
 
-    std::string description() const override {
-        std::string result = fModifiers.description() + fInterfaceName + " {\n";
+    SkString description() const override {
+        SkString result = fModifiers.description() + fInterfaceName + " {\n";
         for (size_t i = 0; i < fDeclarations.size(); i++) {
             result += fDeclarations[i]->description() + "\n";
         }
         result += "}";
-        if (fValueName.length()) {
+        if (fValueName.size()) {
             result += " " + fValueName;
         }
         return result + ";";
     }
 
     const ASTModifiers fModifiers;
-    const std::string fInterfaceName;
-    const std::string fValueName;
+    const SkString fInterfaceName;
+    const SkString fValueName;
     const std::vector<std::unique_ptr<ASTVarDeclarations>> fDeclarations;
 
     typedef ASTDeclaration INHERITED;
diff --git a/src/sksl/ast/SkSLASTLayout.h b/src/sksl/ast/SkSLASTLayout.h
index ae3c3b6168..cb7f3c175c 100644
--- a/src/sksl/ast/SkSLASTLayout.h
+++ b/src/sksl/ast/SkSLASTLayout.h
@@ -48,7 +48,7 @@ struct ASTLayout : public ASTNode {
         return "";
     }
 
-    static bool ReadFormat(std::string str, Format* format) {
+    static bool ReadFormat(SkString str, Format* format) {
         if (str == "rgba32f") {
             *format = Format::kRGBA32F;
             return true;
@@ -90,9 +90,9 @@ struct ASTLayout : public ASTNode {
     , fBlendSupportAllEquations(blendSupportAllEquations)
     , fFormat(format) {}
 
-    std::string description() const {
-        std::string result;
-        std::string separator;
+    SkString description() const {
+        SkString result;
+        SkString separator;
         if (fLocation >= 0) {
             result += separator + "location = " + to_string(fLocation);
             separator = ", ";
@@ -129,7 +129,7 @@ struct ASTLayout : public ASTNode {
             result += separator + FormatToStr(fFormat);
             separator = ", ";
         }
-        if (result.length() > 0) {
+        if (result.size() > 0) {
             result = "layout (" + result + ")";
         }
         return result;
diff --git a/src/sksl/ast/SkSLASTModifiers.h b/src/sksl/ast/SkSLASTModifiers.h
index 61d2e9f25d..734169267c 100644
--- a/src/sksl/ast/SkSLASTModifiers.h
+++ b/src/sksl/ast/SkSLASTModifiers.h
@@ -34,8 +34,8 @@ struct ASTModifiers : public ASTNode {
     : fLayout(layout)
     , fFlags(flags) {}
 
-    std::string description() const override {
-        std::string result = fLayout.description();
+    SkString description() const override {
+        SkString result = fLayout.description();
         if (fFlags & kUniform_Flag) {
             result += "uniform ";
         }
diff --git a/src/sksl/ast/SkSLASTModifiersDeclaration.h b/src/sksl/ast/SkSLASTModifiersDeclaration.h
index f5cc620899..07efdf6024 100644
--- a/src/sksl/ast/SkSLASTModifiersDeclaration.h
+++ b/src/sksl/ast/SkSLASTModifiersDeclaration.h
@@ -23,7 +23,7 @@ struct ASTModifiersDeclaration : public ASTDeclaration {
     : INHERITED(Position(), kModifiers_Kind)
     , fModifiers(modifiers) {}
 
-    std::string description() const {
+    SkString description() const {
         return fModifiers.description() + ";";
     }
 
diff --git a/src/sksl/ast/SkSLASTNode.h b/src/sksl/ast/SkSLASTNode.h
index 4305011fa5..af065955f8 100644
--- a/src/sksl/ast/SkSLASTNode.h
+++ b/src/sksl/ast/SkSLASTNode.h
@@ -8,8 +8,7 @@
 #ifndef SKSL_ASTNODE
 #define SKSL_ASTNODE
 
-#include <memory>
-#include <string>
+#include "SkString.h"
 
 namespace SkSL {
 
@@ -20,7 +19,7 @@ namespace SkSL {
 struct ASTNode {
     virtual ~ASTNode() {}
      
-    virtual std::string description() const = 0;
+    virtual SkString description() const = 0;
 };
 
 } // namespace
diff --git a/src/sksl/ast/SkSLASTParameter.h b/src/sksl/ast/SkSLASTParameter.h
index 8f1b4535f2..b1fd658434 100644
--- a/src/sksl/ast/SkSLASTParameter.h
+++ b/src/sksl/ast/SkSLASTParameter.h
@@ -20,15 +20,15 @@ struct ASTParameter : public ASTPositionNode {
     // 'sizes' is a list of the array sizes appearing on a parameter, in source order. 
     // e.g. int x[3][1] would have sizes [3, 1].
     ASTParameter(Position position, ASTModifiers modifiers, std::unique_ptr<ASTType> type, 
-                 std::string name, std::vector<int> sizes)
+                 SkString name, std::vector<int> sizes)
     : INHERITED(position)
     , fModifiers(modifiers)
     , fType(std::move(type))
     , fName(std::move(name))
     , fSizes(std::move(sizes)) {}
 
-    std::string description() const override {
-        std::string result = fModifiers.description() + fType->description() + " " + fName;
+    SkString description() const override {
+        SkString result = fModifiers.description() + fType->description() + " " + fName;
         for (int size : fSizes) {
             result += "[" + to_string(size) + "]";
         }
@@ -37,7 +37,7 @@ struct ASTParameter : public ASTPositionNode {
 
     const ASTModifiers fModifiers;
     const std::unique_ptr<ASTType> fType;
-    const std::string fName;
+    const SkString fName;
     const std::vector<int> fSizes;
 
     typedef ASTPositionNode INHERITED;
diff --git a/src/sksl/ast/SkSLASTPrecision.h b/src/sksl/ast/SkSLASTPrecision.h
index a7df57948e..a2f427c9ce 100644
--- a/src/sksl/ast/SkSLASTPrecision.h
+++ b/src/sksl/ast/SkSLASTPrecision.h
@@ -22,17 +22,17 @@ struct ASTPrecision : public ASTDeclaration {
     : INHERITED(position, kPrecision_Kind)
     , fPrecision(precision) {}
 
-    std::string description() const {
+    SkString description() const {
         switch (fPrecision) {
-            case Modifiers::kLowp_Flag: return "precision lowp float;";
-            case Modifiers::kMediump_Flag: return "precision mediump float;";
-            case Modifiers::kHighp_Flag: return "precision highp float;";
+            case Modifiers::kLowp_Flag: return SkString("precision lowp float;");
+            case Modifiers::kMediump_Flag: return SkString("precision mediump float;");
+            case Modifiers::kHighp_Flag: return SkString("precision highp float;");
             default: 
                 ASSERT(false); 
-                return "<error>";
+                return SkString("<error>");
         }
         ASSERT(false);
-        return "<error>";
+        return SkString("<error>");
     }
 
     const Modifiers::Flag fPrecision;
diff --git a/src/sksl/ast/SkSLASTPrefixExpression.h b/src/sksl/ast/SkSLASTPrefixExpression.h
index 0d326e2aab..e06ec41f9e 100644
--- a/src/sksl/ast/SkSLASTPrefixExpression.h
+++ b/src/sksl/ast/SkSLASTPrefixExpression.h
@@ -22,7 +22,7 @@ struct ASTPrefixExpression : public ASTExpression {
     , fOperator(op.fKind)
     , fOperand(std::move(operand)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return Token::OperatorName(fOperator) + fOperand->description();
     }
 
diff --git a/src/sksl/ast/SkSLASTReturnStatement.h b/src/sksl/ast/SkSLASTReturnStatement.h
index 3aac783a8c..ed24d4a153 100644
--- a/src/sksl/ast/SkSLASTReturnStatement.h
+++ b/src/sksl/ast/SkSLASTReturnStatement.h
@@ -21,8 +21,8 @@ struct ASTReturnStatement : public ASTStatement {
     : INHERITED(position, kReturn_Kind)
     , fExpression(std::move(expression)) {}
 
-    std::string description() const override {
-        std::string result("return");
+    SkString description() const override {
+        SkString result("return");
         if (fExpression) {
             result += " " + fExpression->description();
         }
diff --git a/src/sksl/ast/SkSLASTSuffix.h b/src/sksl/ast/SkSLASTSuffix.h
index 18f79f01ea..64178c7682 100644
--- a/src/sksl/ast/SkSLASTSuffix.h
+++ b/src/sksl/ast/SkSLASTSuffix.h
@@ -30,12 +30,12 @@ struct ASTSuffix : public ASTPositionNode {
     : INHERITED(position)
     , fKind(kind) {}
 
-    std::string description() const override {
+    SkString description() const override {
         switch (fKind) {
             case kPostIncrement_Kind:
-                return "++";
+                return SkString("++");
             case kPostDecrement_Kind:
-                return "--";
+                return SkString("--");
             default:
                 ABORT("unsupported suffix operator");
         }        
diff --git a/src/sksl/ast/SkSLASTSuffixExpression.h b/src/sksl/ast/SkSLASTSuffixExpression.h
index c0fda294b9..7ee200fd43 100644
--- a/src/sksl/ast/SkSLASTSuffixExpression.h
+++ b/src/sksl/ast/SkSLASTSuffixExpression.h
@@ -22,7 +22,7 @@ struct ASTSuffixExpression : public ASTExpression {
     , fBase(std::move(base))
     , fSuffix(std::move(suffix)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return fBase->description() + fSuffix->description();
     }
 
diff --git a/src/sksl/ast/SkSLASTTernaryExpression.h b/src/sksl/ast/SkSLASTTernaryExpression.h
index 20b827a049..ddf8e3d120 100644
--- a/src/sksl/ast/SkSLASTTernaryExpression.h
+++ b/src/sksl/ast/SkSLASTTernaryExpression.h
@@ -24,7 +24,7 @@ struct ASTTernaryExpression : public ASTExpression {
     , fIfTrue(std::move(ifTrue))
     , fIfFalse(std::move(ifFalse)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return "(" + fTest->description() + " ? " + fIfTrue->description() + " : " +
                fIfFalse->description() + ")";        
     }
diff --git a/src/sksl/ast/SkSLASTType.h b/src/sksl/ast/SkSLASTType.h
index b8fdedb214..81594000e5 100644
--- a/src/sksl/ast/SkSLASTType.h
+++ b/src/sksl/ast/SkSLASTType.h
@@ -19,16 +19,16 @@ struct ASTType : public ASTPositionNode {
         kStruct_Kind
     };
 
-    ASTType(Position position, std::string name, Kind kind)
+    ASTType(Position position, SkString name, Kind kind)
     : INHERITED(position)
     , fName(std::move(name))
     , fKind(kind) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return fName;
     }
 
-    const std::string fName;
+    const SkString fName;
 
     const Kind fKind;
 
diff --git a/src/sksl/ast/SkSLASTVarDeclaration.h b/src/sksl/ast/SkSLASTVarDeclaration.h
index 066922fb85..9de4cf55b9 100644
--- a/src/sksl/ast/SkSLASTVarDeclaration.h
+++ b/src/sksl/ast/SkSLASTVarDeclaration.h
@@ -22,15 +22,15 @@ namespace SkSL {
  * instances.
  */
 struct ASTVarDeclaration {
-    ASTVarDeclaration(const std::string name,
+    ASTVarDeclaration(const SkString name,
                       std::vector<std::unique_ptr<ASTExpression>> sizes,
                       std::unique_ptr<ASTExpression> value)
     : fName(name)
     , fSizes(std::move(sizes))
     , fValue(std::move(value)) {}
 
-    std::string description() const {
-        std::string result = fName;
+    SkString description() const {
+        SkString result = fName;
         for (const auto& size : fSizes) {
             if (size) {
                 result += "[" + size->description() + "]";
@@ -44,7 +44,7 @@ struct ASTVarDeclaration {
         return result;        
     }
 
-    std::string fName;
+    SkString fName;
 
     // array sizes, if any. e.g. 'foo[3][]' has sizes [3, null]
     std::vector<std::unique_ptr<ASTExpression>> fSizes;
@@ -65,9 +65,9 @@ struct ASTVarDeclarations : public ASTDeclaration {
     , fType(std::move(type))
     , fVars(std::move(vars)) {}
 
-    std::string description() const override {
-        std::string result = fModifiers.description() + fType->description() + " ";
-        std::string separator = "";
+    SkString description() const override {
+        SkString result = fModifiers.description() + fType->description() + " ";
+        SkString separator;
         for (const auto& var : fVars) {
             result += separator;
             separator = ", ";
diff --git a/src/sksl/ast/SkSLASTVarDeclarationStatement.h b/src/sksl/ast/SkSLASTVarDeclarationStatement.h
index 8bae389146..d71639d797 100644
--- a/src/sksl/ast/SkSLASTVarDeclarationStatement.h
+++ b/src/sksl/ast/SkSLASTVarDeclarationStatement.h
@@ -21,7 +21,7 @@ struct ASTVarDeclarationStatement : public ASTStatement {
     : INHERITED(decl->fPosition, kVarDeclaration_Kind)
     , fDeclarations(std::move(decl)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return fDeclarations->description() + ";";
     }
 
diff --git a/src/sksl/ast/SkSLASTWhileStatement.h b/src/sksl/ast/SkSLASTWhileStatement.h
index e29aa23e4a..853ac8028d 100644
--- a/src/sksl/ast/SkSLASTWhileStatement.h
+++ b/src/sksl/ast/SkSLASTWhileStatement.h
@@ -22,7 +22,7 @@ struct ASTWhileStatement : public ASTStatement {
     , fTest(std::move(test))
     , fStatement(std::move(statement)) {}
 
-    std::string description() const override {
+    SkString description() const override {
         return "while (" + fTest->description() + ") " + fStatement->description();
     }