Don't allow elevation for CHROME_OS.

chrome/browser/managed_mode/managed_mode_navigation_observer.cc

Index: chrome/browser/managed_mode/managed_mode_navigation_observer.cc
diff --git a/chrome/browser/managed_mode/managed_mode_navigation_observer.cc b/chrome/browser/managed_mode/managed_mode_navigation_observer.cc
index ce1d91834f92b4ed4c3289556947babd40708948..4d54ff612118ad213831d262bae9097d54e7abd6 100644
--- a/chrome/browser/managed_mode/managed_mode_navigation_observer.cc
+++ b/chrome/browser/managed_mode/managed_mode_navigation_observer.cc
@@ -333,11 +333,19 @@ void ManagedModeNavigationObserver::AddSavedURLsToWhitelistAndClearState() {
 }
 
 bool ManagedModeNavigationObserver::is_elevated() const {
+#if defined(OS_CHROMEOS)
+  return false;
+#else
   return is_elevated_;
+#endif
 }
 
 void ManagedModeNavigationObserver::set_elevated(bool is_elevated) {
+#if defined(OS_CHROMEOS)
   is_elevated_ = is_elevated;
+#else
+  NOTREACHED();
+#endif
 }
 
 void ManagedModeNavigationObserver::AddURLToPatternList(const GURL& url) {