test: add public api golden files

Includes a few style fixes on "* as foo" imports.

tools/public_api_guard/platform-browser/testing.d.ts

@@ -0,0 +1,40 @@
+export declare var browserDetection: BrowserDetection;
+
+export declare class BrowserDetection {
+    static setup(): void;
+    constructor(ua: string);
+    isFirefox: boolean;
+    isAndroid: boolean;
+    isEdge: boolean;
+    isIE: boolean;
+    isWebkit: boolean;
+    isIOS7: boolean;
+    isSlow: boolean;
+    supportsIntlApi: boolean;
+    isChromeDesktop: boolean;
+}
+
+export declare function dispatchEvent(element: any, eventType: any): void;
+
+export declare function el(html: string): HTMLElement;
+
+export declare var expect: (actual: any) => NgMatchers;
+
+export interface NgMatchers extends jasmine.Matchers {
+    toBePromise(): boolean;
+    toBeAnInstanceOf(expected: any): boolean;
+    toHaveText(expected: any): boolean;
+    toHaveCssClass(expected: any): boolean;
+    toHaveCssStyle(expected: any): boolean;
+    toImplement(expected: any): boolean;
+    toContainError(expected: any): boolean;
+    not: NgMatchers;
+}
+
+export declare function normalizeCSS(css: string): string;
+
+export declare function stringifyElement(el: any): string;
+
+export declare const TEST_BROWSER_APPLICATION_PROVIDERS: Array<any>;
+
+export declare const TEST_BROWSER_PLATFORM_PROVIDERS: Array<any>;