Update SymbolWalker tests

...to consume revised API.

Author: amcasey

src/harness/unittests/symbolWalker.ts

@@ -2,21 +2,19 @@
 
 namespace ts {
     describe("Symbol Walker", () => {
-        function test(description: string, source: string, verifier: (file: SourceFile, checker: TypeChecker, walker: SymbolWalker) => void) {
+        function test(description: string, source: string, verifier: (file: SourceFile, checker: TypeChecker) => void) {
             it(description, () => {
                 let {result} = Harness.Compiler.compileFiles([{
                     unitName: "main.ts",
                     content: source
                 }], [], {}, {}, "/");
                 let file = result.program.getSourceFile("main.ts");
                 let checker = result.program.getTypeChecker();
-                let walker = checker.getSymbolWalker();
-                verifier(file, checker, walker);
+                verifier(file, checker);
 
                 result = undefined;
                 file = undefined;
                 checker = undefined;
-                walker = undefined;
             });
         }
 
@@ -26,11 +24,11 @@ interface Bar {
     y: number;
     history: Bar[];
 }
-export default function foo(a: number, b: Bar): void {}`, (file, checker, walker) => {
+export default function foo(a: number, b: Bar): void {}`, (file, checker) => {
             let foundCount = 0;
             let stdLibRefSymbols = 0;
             const expectedSymbols = ["default", "a", "b", "Bar", "x", "y", "history"];
-            walker.reset(symbol => {
+            let walker = checker.getSymbolWalker(symbol => {
                 const isStdLibSymbol = forEach(symbol.declarations, d => {
                     return getSourceFileOfNode(d).hasNoDefaultLib;
                 });
@@ -44,7 +42,7 @@ export default function foo(a: number, b: Bar): void {}`, (file, checker, walker
             });
             const symbols = checker.getExportsOfModule(file.symbol);
             for (const symbol of symbols) {
-                walker.visitSymbol(symbol);
+                walker.walkSymbol(symbol);
             }
             assert.equal(foundCount, expectedSymbols.length);
             assert.equal(stdLibRefSymbols, 1); // Expect 1 stdlib entry symbol - the implicit Array referenced by Bar.history