Delete the last remaining use of OVERRIDE and remove its definition.

TBR=dominich@chromium.org,thestig@chromium.org
BUG=417463

Review URL: https://codereview.chromium.org/666563003

Cr-Commit-Position: refs/heads/master@{#300642}

base/compiler_specific.h

@@ -139,12 +139,6 @@
 #define ALIGNOF(type) __alignof__(type)
 #endif
 
-// Annotate a virtual method indicating it must be overriding a virtual
-// method in the parent class.
-// Use like:
-//   virtual void foo() OVERRIDE;
-#define OVERRIDE override
-
 // Annotate a function indicating the caller must examine the return value.
 // Use like:
 //   int foo() WARN_UNUSED_RESULT;

chrome/browser/predictors/resource_prefetch_common_unittest.cc

@@ -27,14 +27,14 @@ namespace {
 
 class MockNetworkChangeNotifierWIFI : public NetworkChangeNotifier {
  public:
-  ConnectionType GetCurrentConnectionType() const OVERRIDE {
+  ConnectionType GetCurrentConnectionType() const override {
     return NetworkChangeNotifier::CONNECTION_WIFI;
   }
 };
 
 class MockNetworkChangeNotifier4G : public NetworkChangeNotifier {
  public:
-  ConnectionType GetCurrentConnectionType() const OVERRIDE {
+  ConnectionType GetCurrentConnectionType() const override {
     return NetworkChangeNotifier::CONNECTION_4G;
   }
 };
@@ -46,7 +46,7 @@ namespace predictors {
 class ResourcePrefetchCommonTest : public testing::Test {
  public:
   ResourcePrefetchCommonTest();
-  virtual void SetUp() OVERRIDE;
+  void SetUp() override;
 
   void CreateTestFieldTrial(const std::string& name,
                             const std::string& group_name) {