C++ Ninja编译Chromium嵌入式框架失败，出现错误：抽象类标记为'；最终'；

我正在尝试使用以下方法从源代码处编译CEF：

编译失败：错误：抽象类标记为“final”[-Werror，-Wabstract final class]

In file included from ../../third_party/WebKit/Source/web/ContextMenuClientImpl.cpp:47:
../../third_party/WebKit/Source/web/WebViewImpl.h:113:7: error: abstract class is marked 'final' [-Werror,-Wabstract-final-class]
class WebViewImpl FINAL : public WebView
      ^
../../third_party/WebKit/public/web/WebView.h:420:18: note: unimplemented pure virtual method 'setUseExternalPopupMenusThisInstance' in 'WebViewImpl'
    virtual void setUseExternalPopupMenusThisInstance(bool) = 0;

我想这和编译器有关，我在OSX上

clang++ -v
Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin13.4.0
Thread model: posix

如何成功编译

clang++ -v
Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin13.4.0
Thread model: posix