Try fast-fetch rather than full fetch if drive::FileSystem::GetEntryInfo failed.

chrome/browser/chromeos/drive/file_system_unittest.cc

Index: chrome/browser/chromeos/drive/file_system_unittest.cc
diff --git a/chrome/browser/chromeos/drive/file_system_unittest.cc b/chrome/browser/chromeos/drive/file_system_unittest.cc
index 27a029e2d5000feeb22b45791b40d78e15801472..d9595a7e4a3300f40dd5aa2f33ad923c352125bd 100644
--- a/chrome/browser/chromeos/drive/file_system_unittest.cc
+++ b/chrome/browser/chromeos/drive/file_system_unittest.cc
@@ -461,6 +461,10 @@ class DriveFileSystemTest : public testing::Test {
 };
 
 TEST_F(DriveFileSystemTest, DuplicatedAsyncInitialization) {
+  // "Fast fetch" will fire an OnirectoryChanged event.
+  EXPECT_CALL(*mock_directory_observer_, OnDirectoryChanged(
+      Eq(base::FilePath(FILE_PATH_LITERAL("drive"))))).Times(1);
+
   int counter = 0;
   const GetEntryInfoCallback& callback = base::Bind(
       &AsyncInitializationCallback, &counter, 2, &message_loop_);
@@ -475,8 +479,9 @@ TEST_F(DriveFileSystemTest, DuplicatedAsyncInitialization) {
   // Although GetEntryInfoByPath() was called twice, the account metadata
   // should only be loaded once. In the past, there was a bug that caused
   // it to be loaded twice.
-  EXPECT_EQ(1, fake_drive_service_->about_resource_load_count());
   EXPECT_EQ(1, fake_drive_service_->resource_list_load_count());
+  // See the comment in GetMyDriveRoot test case why this is 2.
+  EXPECT_EQ(2, fake_drive_service_->about_resource_load_count());
 }
 
 TEST_F(DriveFileSystemTest, GetGrandRootEntry) {
@@ -503,18 +508,25 @@ TEST_F(DriveFileSystemTest, GetOtherDirEntry) {
 }
 
 TEST_F(DriveFileSystemTest, GetMyDriveRoot) {
+  // "Fast fetch" will fire an OnirectoryChanged event.
+  EXPECT_CALL(*mock_directory_observer_, OnDirectoryChanged(
+      Eq(base::FilePath(FILE_PATH_LITERAL("drive"))))).Times(1);
+
   const base::FilePath kFilePath(FILE_PATH_LITERAL("drive/root"));
   scoped_ptr<ResourceEntry> entry = GetEntryInfoByPathSync(kFilePath);
   ASSERT_TRUE(entry);
   EXPECT_EQ(fake_drive_service_->GetRootResourceId(), entry->resource_id());
 
-  // The changestamp should be propagated to the root directory.
-  EXPECT_EQ(fake_drive_service_->largest_changestamp(),
-            entry->directory_specific_info().changestamp());
+  // Absence of "drive/root" in the local metadata triggers the "fast fetch"
+  // of "drive" directory. Fetch of "drive" grand root directory has a special
+  // implementation. Instead of normal GetResourceListInDirectory(), it is
+  // emulated by calling GetAboutResource() so that the resource_id of
+  // "drive/root" is listed.
+  // Together with the normal GetAboutResource() call to retrieve the largest
+  // changestamp, the method is called twice.
+  EXPECT_EQ(2, fake_drive_service_->about_resource_load_count());
 
-  // The resource load should happen because "My Drive"'s root is not the grand
-  // root entry and hence does not present until the initial loading.
-  EXPECT_EQ(1, fake_drive_service_->about_resource_load_count());
+  // After "fast fetch" is done, full resource list is fetched.
   EXPECT_EQ(1, fake_drive_service_->resource_list_load_count());
 }
 
@@ -891,6 +903,45 @@ TEST_F(DriveFileSystemTest, OfflineCachedFeedLoading) {
   EXPECT_EQ(1, fake_drive_service_->change_list_load_count());
 }
 
+TEST_F(DriveFileSystemTest, ReadDirectoryWhileRefreshing) {
+  EXPECT_CALL(*mock_directory_observer_, OnDirectoryChanged(_))
+      .Times(AtLeast(1));
+
+  // Enter the "refreshing" state.

[satorux1, 2013/05/07 06:29:45]

Enter the "refreshing" state so the fast fetch will be performed.

[hashimoto, 2013/05/07 06:49:01]

Done for ReadDirectoryWhileRefreshing and
GetEntryInfoNonExistentWhileRefreshing.

+  ASSERT_TRUE(SaveTestFileSystem(USE_OLD_TIMESTAMP));
+  file_system_->CheckForUpdates();
+
+  // The list of resources in "drive/root/Dir1" should be fetched.
+  EXPECT_TRUE(ReadDirectoryByPathSync(base::FilePath(
+      FILE_PATH_LITERAL("drive/root/Dir1"))));
+  EXPECT_EQ(1, fake_drive_service_->directory_load_count());
+}
+
+TEST_F(DriveFileSystemTest, GetEntryInfoExistingWhileRefreshing) {
+  // Enter the "refreshing" state.
+  ASSERT_TRUE(SaveTestFileSystem(USE_OLD_TIMESTAMP));
+  file_system_->CheckForUpdates();
+
+  // If an entry is already found in local metadata, no directory fetch happens.
+  EXPECT_TRUE(GetEntryInfoByPathSync(base::FilePath(
+      FILE_PATH_LITERAL("drive/root/Dir1/File2"))));
+  EXPECT_EQ(0, fake_drive_service_->directory_load_count());
+}
+
+TEST_F(DriveFileSystemTest, GetEntryInfoNonExistentWhileRefreshing) {
+  EXPECT_CALL(*mock_directory_observer_, OnDirectoryChanged(_))
+      .Times(AtLeast(1));
+
+  // Enter the "refreshing" state.
+  ASSERT_TRUE(SaveTestFileSystem(USE_OLD_TIMESTAMP));
+  file_system_->CheckForUpdates();
+
+  // If an entry is not found, parent directory's resource list is fetched.
+  EXPECT_FALSE(GetEntryInfoByPathSync(base::FilePath(
+      FILE_PATH_LITERAL("drive/root/Dir1/NonExistentFile"))));
+  EXPECT_EQ(1, fake_drive_service_->directory_load_count());
+}
+
 TEST_F(DriveFileSystemTest, TransferFileFromLocalToRemote_RegularFile) {
   fake_free_disk_space_getter_->set_fake_free_disk_space(kLotsOfSpace);