Cleanup: Better constify some strings in chrome/browser/{chromeos,extensions}.

chrome/browser/extensions/extension_keybinding_apitest.cc

Index: chrome/browser/extensions/extension_keybinding_apitest.cc
diff --git a/chrome/browser/extensions/extension_keybinding_apitest.cc b/chrome/browser/extensions/extension_keybinding_apitest.cc
index aba521dc53d4fdb25a7682cd5824f75a2a6c6ddf..026ff9ac707eb0291a8c2c2303e62bc046af73e4 100644
--- a/chrome/browser/extensions/extension_keybinding_apitest.cc
+++ b/chrome/browser/extensions/extension_keybinding_apitest.cc
@@ -373,9 +373,9 @@ IN_PROC_BROWSER_TEST_F(CommandsApiTest,
   const Extension* extension = GetSingleLoadedExtension();
   // Simulate the user setting the keybinding to Ctrl+D.
 #if defined(OS_MACOSX)
-  const char* hotkey = "Command+D";
+  const char hotkey[] = "Command+D";
 #else
-  const char* hotkey = "Ctrl+D";
+  const char hotkey[] = "Ctrl+D";
 #endif  // defined(OS_MACOSX)
   command_service->UpdateKeybindingPrefs(
       extension->id(), manifest_values::kBrowserActionCommandEvent, hotkey);