Fix threading bug in the brlapi braille controller

chrome/browser/extensions/api/braille_display_private/braille_display_private_apitest.cc

Index: chrome/browser/extensions/api/braille_display_private/braille_display_private_apitest.cc
diff --git a/chrome/browser/extensions/api/braille_display_private/braille_display_private_apitest.cc b/chrome/browser/extensions/api/braille_display_private/braille_display_private_apitest.cc
index 88ce9b67422b27786c0d44939feb5469a87c4f53..436ea52963b37990a91046a7c7d6d5950b93643f 100644
--- a/chrome/browser/extensions/api/braille_display_private/braille_display_private_apitest.cc
+++ b/chrome/browser/extensions/api/braille_display_private/braille_display_private_apitest.cc
@@ -88,7 +88,7 @@ class MockBrlapiConnection : public BrlapiConnection {
     return true;
   }
 
-  virtual int ReadKey(brlapi_keyCode_t* key_code) {
+  virtual int ReadKey(brlapi_keyCode_t* key_code) OVERRIDE {
     if (!data_->pending_keys.empty()) {
       int queued_key_code = data_->pending_keys.front();
       data_->pending_keys.pop_front();
@@ -120,7 +120,7 @@ class MockBrlapiConnection : public BrlapiConnection {
 
 class BrailleDisplayPrivateApiTest : public ExtensionApiTest {
  public:
-  virtual void SetUpInProcessBrowserTestFixture() {
+  virtual void SetUpInProcessBrowserTestFixture() OVERRIDE {
     ExtensionApiTest::SetUpInProcessBrowserTestFixture();
     connection_data_.connected = false;
     connection_data_.display_size = 0;