Enable Clang warnings in .cc files for Linux+[Aura/ChromeOS]

chrome/browser/chromeos/system/ash_system_tray_delegate.cc

Index: chrome/browser/chromeos/system/ash_system_tray_delegate.cc
diff --git a/chrome/browser/chromeos/system/ash_system_tray_delegate.cc b/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
index c15301c0d865763ed35b2d9e09ca57e6570f3d5e..025e1fabb5f9adfe6437336fd83987e83b55b33b 100644
--- a/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
+++ b/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
@@ -1402,18 +1402,18 @@ class SystemTrayDelegate : public ash::SystemTrayDelegate,
   }
 
   // drive::JobListObserver overrides.
-  virtual void OnJobAdded(const drive::JobInfo& job_info) {
+  virtual void OnJobAdded(const drive::JobInfo& job_info) OVERRIDE {
     OnJobUpdated(job_info);
   }
 
   virtual void OnJobDone(const drive::JobInfo& job_info,
-                         drive::FileError error) {
+                         drive::FileError error) OVERRIDE {
     ash::DriveOperationStatus status;
     if (ConvertToFinishedDriveOperationStatus(job_info, error, &status))
       GetSystemTrayNotifier()->NotifyDriveJobUpdated(status);
   }
 
-  virtual void OnJobUpdated(const drive::JobInfo& job_info) {
+  virtual void OnJobUpdated(const drive::JobInfo& job_info) OVERRIDE {
     ash::DriveOperationStatus status;
     if (ConvertToDriveOperationStatus(job_info, &status))
       GetSystemTrayNotifier()->NotifyDriveJobUpdated(status);