Bug 1171708 - Add flushWindow method to TabStateFlusher. r=billm

--HG--
extra : commitid : H3Y1P9Mj63v
extra : rebase_source : 96c93f0b6fc6a9befe4dad4a0f47902279156474
extra : source : 82c9750d88e204516d04eaa91209e7bec691b57c

browser/components/sessionstore/TabStateFlusher.jsm

@@ -27,6 +27,14 @@ this.TabStateFlusher = Object.freeze({
     return TabStateFlusherInternal.flush(browser);
   },
 
+  /**
+   * Requests an async flush for all browsers of a given window. Returns a Promise
+   * that will resolve when we've heard back from all browsers.
+   */
+  flushWindow(window) {
+    return TabStateFlusherInternal.flushWindow(window);
+  },
+
   /**
    * Resolves the flush request with the given flush ID.
    */
@@ -75,6 +83,16 @@ var TabStateFlusherInternal = {
     });
   },
 
+  /**
+   * Requests an async flush for all browsers of a given window. Returns a Promise
+   * that will resolve when we've heard back from all browsers.
+   */
+  flushWindow(window) {
+    let browsers = window.gBrowser.browsers;
+    let promises = browsers.map((browser) => this.flush(browser));
+    return Promise.all(promises);
+  },
+
   /**
    * Resolves the flush request with the given flush ID.
    */