chore(typings): remove StringMap

This was a poorly typed attempt to mimic TypeScript's index signatures,
which we can use instead.
This eliminates a very strange type that we were exposing to users, but
not re-exporting through our public API.

Fixes #4483

modules/benchpress/test/metric/multi_metric_spec.ts

@@ -11,7 +11,7 @@ import {
   xit,
 } from 'angular2/test_lib';
 
-import {ListWrapper, StringMap} from 'angular2/src/core/facade/collection';
+import {ListWrapper} from 'angular2/src/core/facade/collection';
 import {PromiseWrapper, Promise} from 'angular2/src/core/facade/async';
 
 import {Metric, MultiMetric, bind, Injector} from 'benchpress/common';
@@ -70,13 +70,13 @@ class MockMetric extends Metric {
 
   beginMeasure(): Promise<string> { return PromiseWrapper.resolve(`${this._id}_beginMeasure`); }
 
-  endMeasure(restart: boolean): Promise<StringMap<string, any>> {
+  endMeasure(restart: boolean): Promise<{[key: string]: any}> {
     var result = {};
     result[this._id] = {'restart': restart};
     return PromiseWrapper.resolve(result);
   }
 
-  describe(): StringMap<string, string> {
+  describe(): {[key: string]: string} {
     var result = {};
     result[this._id] = 'describe';
     return result;

modules/benchpress/test/reporter/multi_reporter_spec.ts

@@ -11,7 +11,7 @@ import {
   xit,
 } from 'angular2/test_lib';
 
-import {ListWrapper, StringMap} from 'angular2/src/core/facade/collection';
+import {ListWrapper} from 'angular2/src/core/facade/collection';
 import {PromiseWrapper, Promise} from 'angular2/src/core/facade/async';
 import {DateWrapper} from 'angular2/src/core/facade/lang';
 
@@ -65,12 +65,12 @@ export function main() {
 class MockReporter extends Reporter {
   constructor(private _id: string) { super(); }
 
-  reportMeasureValues(values: MeasureValues): Promise<StringMap<string, any>> {
+  reportMeasureValues(values: MeasureValues): Promise<{[key: string]: any}> {
     return PromiseWrapper.resolve({'id': this._id, 'values': values});
   }
 
   reportSample(completeSample: MeasureValues[],
-               validSample: MeasureValues[]): Promise<StringMap<string, any>> {
+               validSample: MeasureValues[]): Promise<{[key: string]: any}> {
     return PromiseWrapper.resolve(
         {'id': this._id, 'completeSample': completeSample, 'validSample': validSample});
   }

modules/benchpress/test/web_driver_extension_spec.ts

@@ -11,7 +11,7 @@ import {
   xit,
 } from 'angular2/test_lib';
 
-import {StringMap, ListWrapper} from 'angular2/src/core/facade/collection';
+import {ListWrapper} from 'angular2/src/core/facade/collection';
 import {isPresent, StringWrapper} from 'angular2/src/core/facade/lang';
 import {PromiseWrapper} from 'angular2/src/core/facade/async';
 
@@ -57,7 +57,7 @@ class MockExtension extends WebDriverExtension {
     this.id = id;
   }
 
-  supports(capabilities: StringMap<string, any>): boolean {
+  supports(capabilities: {[key: string]: any}): boolean {
     return StringWrapper.equals(capabilities['browser'], this.id);
   }
 }