drive: Make FileManagerBrowserTest more robust

chrome/test/data/extensions/api_test/file_manager_browsertest/background.js

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // These must match the files created in the C++ code.
 var EXPECTED_FILES_BEFORE = [
   ['hello.txt', '123 bytes', 'Plain text', 'Sep 4, 1998 12:34 PM'],
   ['world.mpeg', '1,000 bytes', 'MPEG video', 'Jul 4, 2012 10:35 AM'],
   ['My Desktop Background.png', '1 KB', 'PNG image', 'Jan 18, 2038 1:02 AM'],
   ['photos', '--', 'Folder', 'Jan 1, 1980 11:59 PM']
@@ skipping 66 matching lines @@
       else
         window.setTimeout(helper, 50);
     });
   }
   helper();
 }
 
 // Checks that the files initially added by the C++ side are displayed, and
 // that a subsequently added file shows up.
 function testFileDisplay() {
-  getFileList(function(actualFilesBefore) {
-    chrome.test.assertEq(EXPECTED_FILES_BEFORE, actualFilesBefore);
-    chrome.test.sendMessage('initial check done', function(reply) {
-      chrome.test.assertEq('file added', reply);
-      waitForFileListChange(
+  waitForFileListChange(
+    0,
+    function(actualFilesBefore) {
+      chrome.test.assertEq(EXPECTED_FILES_BEFORE, actualFilesBefore);
+      chrome.test.sendMessage('initial check done', function(reply) {
+        chrome.test.assertEq('file added', reply);
+        waitForFileListChange(
           EXPECTED_FILES_BEFORE.length,
           chrome.test.callbackPass(function(actualFilesAfter) {
             chrome.test.assertEq(EXPECTED_FILES_AFTER, actualFilesAfter);
           }));
+      });
     });
-  });
 }
 
 // Injects the keyboard test code into the file manager tab and runs the
 // keyboard delete test.
 function doKeyboardTestWithConfirmation(code) {
-  chrome.tabs.executeScript(null, {file: 'fake_keypress.js'}, function(result) {
-    chrome.tabs.executeScript(null, {code: code}, function(result) {
-      chrome.test.assertFalse(!result[0]);
-      waitAndAcceptDialog(function() {
-        // Succeed here if anything happens; the C++ code checks what happened.
-        waitForFileListChange(EXPECTED_FILES_BEFORE.length,
-                              chrome.test.succeed);
+  // Wait until the file list is rendered.
+  waitForFileListChange(
+    0,
+    function(unused) {
+      // Once the file list is rendered, start the keyboard test.
+      chrome.tabs.executeScript(
+          null, {file: 'fake_keypress.js'}, function(result) {
+        chrome.tabs.executeScript(null, {code: code}, function(result) {
+          chrome.test.assertFalse(!result[0]);
+          waitAndAcceptDialog(function() {
+            // Succeed here if anything happens; the C++ code checks what
+            // happened.
+            waitForFileListChange(EXPECTED_FILES_BEFORE.length,
+                                  chrome.test.succeed);
+          });
+        });
       });
     });
-  });
 }
 
 // Injects the keyboard test code into the file manager tab and runs the
 // keyboard copy test.
 function doKeyboardTest(code) {
-  chrome.tabs.executeScript(null, {file: 'fake_keypress.js'}, function(result) {
-    chrome.tabs.executeScript(null, {code: code}, function(result) {
-      chrome.test.assertFalse(!result[0]);
-      // Succeed here if anything happens; the C++ code checks what happened.
-      waitForFileListChange(EXPECTED_FILES_BEFORE.length, chrome.test.succeed);
+  waitForFileListChange(
+    0,
+    function(unused) {
+      chrome.tabs.executeScript(
+          null, {file: 'fake_keypress.js'}, function(result) {
+        chrome.tabs.executeScript(null, {code: code}, function(result) {
+          chrome.test.assertFalse(!result[0]);
+          // Succeed here if anything happens; the C++ code checks what
+          // happened.
+          waitForFileListChange(EXPECTED_FILES_BEFORE.length,
+                                chrome.test.succeed);
+        });
+      });
     });
-  });
 }
 
 chrome.test.runTests([
   // Waits for the C++ code to send a string identifying a test, then runs that
   // test.
   function testRunner() {
     chrome.test.sendMessage('which test', function(reply) {
       // These test names are provided by file_manager_browsertest.cc.
       if (reply === 'file display') {
         testFileDisplay();
       } else if (reply === 'keyboard copy') {
         doKeyboardTest('fakeFileCopy("world.mpeg");');
       } else if (reply === 'keyboard delete') {
         doKeyboardTestWithConfirmation('fakeFileDelete("world.mpeg");');
       } else {
         chrome.test.fail('Bogus test name passed to testRunner()');
       }
     });
   }
 ]);