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

chrome/browser/extensions/platform_app_browsertest.cc

Index: chrome/browser/extensions/platform_app_browsertest.cc
diff --git a/chrome/browser/extensions/platform_app_browsertest.cc b/chrome/browser/extensions/platform_app_browsertest.cc
index 29a98c9062b9926707c6dc069e434d6033526144..642f948fe2c477810259628f79899b5d3bf565f5 100644
--- a/chrome/browser/extensions/platform_app_browsertest.cc
+++ b/chrome/browser/extensions/platform_app_browsertest.cc
@@ -936,11 +936,11 @@ class PlatformAppIncognitoBrowserTest : public PlatformAppBrowserTest,
   }
 
   // ShellWindowRegistry::Observer implementation.
-  virtual void OnShellWindowAdded(ShellWindow* shell_window) {
+  virtual void OnShellWindowAdded(ShellWindow* shell_window) OVERRIDE {
     opener_app_ids_.insert(shell_window->extension()->id());
   }
-  virtual void OnShellWindowIconChanged(ShellWindow* shell_window) {}
-  virtual void OnShellWindowRemoved(ShellWindow* shell_window) {}
+  virtual void OnShellWindowIconChanged(ShellWindow* shell_window) OVERRIDE {}
+  virtual void OnShellWindowRemoved(ShellWindow* shell_window) OVERRIDE {}
 
  protected:
   // A set of ids of apps we've seen open a shell window.