Fix FileDialog tests with flag MyFilesVolume enabled

Change the test helper function openAndWaitForClosingDialog to wait for
isFileManagerLoaded instead of waiting for the default entry set as a
way to determine if the Files app has finished loading.

Enable some FileDialog tests to run with flag MyFilesVolume enabled.

Test: --gtest_filter="FileDialog/FilesAppBrowserTest.*"
Bug: 873539
Change-Id: I26177fcbe32bdd285c8067ccf85f1f8fa329502f
Reviewed-on: https://chromium-review.googlesource.com/c/1345380Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609907}

chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

@@ -625,17 +625,37 @@ WRAPPED_INSTANTIATE_TEST_CASE_P(
     FilesAppBrowserTest,
     ::testing::Values(
         TestCase("openFileDialogUnload").WithBrowser(),
+        TestCase("openFileDialogUnload").WithBrowser().EnableMyFilesVolume(),
         TestCase("openFileDialogDownloads").WithBrowser(),
+        TestCase("openFileDialogDownloads").WithBrowser().EnableMyFilesVolume(),
         TestCase("openFileDialogDownloads").WithBrowser().InGuestMode(),
+        TestCase("openFileDialogDownloads")
+            .WithBrowser()
+            .InGuestMode()
+            .EnableMyFilesVolume(),
         TestCase("openFileDialogDownloads").WithBrowser().InIncognito(),
+        TestCase("openFileDialogDownloads")
+            .WithBrowser()
+            .InIncognito()
+            .EnableMyFilesVolume(),
         TestCase("openFileDialogCancelDownloads").WithBrowser(),
+        TestCase("openFileDialogCancelDownloads")
+            .WithBrowser()
+            .EnableMyFilesVolume(),
         TestCase("openFileDialogEscapeDownloads").WithBrowser(),
+        TestCase("openFileDialogEscapeDownloads")
+            .WithBrowser()
+            .EnableMyFilesVolume(),
         TestCase("openFileDialogDrive").WithBrowser().DisableDriveFs(),
         TestCase("openFileDialogDrive")
             .WithBrowser()
             .InIncognito()
             .DisableDriveFs(),
         TestCase("openFileDialogDrive").WithBrowser().EnableDriveFs(),
+        TestCase("openFileDialogDrive")
+            .WithBrowser()
+            .EnableDriveFs()
+            .EnableMyFilesVolume(),
         TestCase("openFileDialogDrive")
             .WithBrowser()
             .InIncognito()

ui/file_manager/integration_tests/file_manager/background.js

@@ -318,15 +318,14 @@ function openAndWaitForClosingDialog(
   return remoteCall.waitForWindow('dialog#').then(function(windowId) {
     return remoteCall.waitForElement(windowId, '#file-list').
         then(function() {
-          // Wait for initialization of the Files app.
-          return remoteCall.waitForFiles(
-              windowId, TestEntryInfo.getExpectedRows(BASIC_LOCAL_ENTRY_SET));
+          return remoteCall.waitFor('isFileManagerLoaded', windowId, true);
         }).
         then(function() {
           return remoteCall.callRemoteTestUtil(
               'selectVolume', windowId, [volumeName]);
         }).
-        then(function() {
+        then(function(result) {
+          chrome.test.assertTrue(result, 'selectVolume failed');
           var expectedRows = TestEntryInfo.getExpectedRows(expectedSet);
           return remoteCall.waitForFiles(windowId, expectedRows);
         }).