This simple piece of code:


  #include "content/public/browser/web_contents_observer.h"
  #include "testing/gmock/include/gmock/gmock.h"
  #include "testing/gtest/include/gtest/gtest.h"

  class MockWebContentsObserver : public content::WebContentsObserver {
   public:
    explicit MockWebContentsObserver(content::WebContents* web_contents)
        : WebContentsObserver(web_contents) {}

    MOCK_METHOD1(DidGetUserInteraction, void(const blink::WebInputEvent::Type type));
  };

  TEST(FooTest, Bar) {
    MockWebContentsObserver observer(nullptr);
    EXPECT_CALL(observer, DidGetUserInteraction(testing::_));
  }


gives following compilation errors on Windows:


error C2220: warning treated as error - no 'object' file generated
warning C4373: 'MockWebContentsObserver::DidGetUserInteraction': virtual function overrides 'content::WebContentsObserver::DidGetUserInteraction', previous versions of the compiler did not override when parameters only differed by const/volatile qualifiers
note: see declaration of 'content::WebContentsObserver::DidGetUserInteraction'
ninja: build stopped: subcommand failed.