chromeos: Add DriveFileSystem::Pin/Unpin

chrome/browser/chromeos/drive/fake_drive_file_system.cc

Index: chrome/browser/chromeos/drive/fake_drive_file_system.cc
diff --git a/chrome/browser/chromeos/drive/fake_drive_file_system.cc b/chrome/browser/chromeos/drive/fake_drive_file_system.cc
index 87f18529b96c1ba6fee45ec2cafca668b95bcd74..deed368ba3a7995a0238e7a98d8488d5838731b0 100644
--- a/chrome/browser/chromeos/drive/fake_drive_file_system.cc
+++ b/chrome/browser/chromeos/drive/fake_drive_file_system.cc
@@ -114,6 +114,16 @@ void FakeDriveFileSystem::CreateFile(const base::FilePath& file_path,
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 }
 
+void FakeDriveFileSystem::Pin(const base::FilePath& file_path,
+                              const FileOperationCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+}
+
+void FakeDriveFileSystem::Unpin(const base::FilePath& file_path,
+                                const FileOperationCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+}
+
 void FakeDriveFileSystem::GetFileByPath(const base::FilePath& file_path,
                                         const GetFileCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));