refactor: move DOCUMENT from platform/browser to common

packages/platform-browser/src/dom/dom_tokens.ts

@@ -8,12 +8,14 @@
 
 import {InjectionToken} from '@angular/core';
 
+import {DOCUMENT as commonDOCUMENT} from '@angular/common';
+
 /**
  * A DI Token representing the main rendering context. In a browser this is the DOM Document.
  *
  * Note: Document might not be available in the Application Context when Application and Rendering
  * Contexts are not the same (e.g. when running the application into a Web Worker).
  *
- * @stable
+ * @deprecated, import from `@angular/common` instead.
  */
-export const DOCUMENT = new InjectionToken<Document>('DocumentToken');
+export const DOCUMENT = commonDOCUMENT;