Update plugin to handle new style rules for virtual annotations.

tools/clang/plugins/FindBadConstructsAction.cpp

Index: tools/clang/plugins/FindBadConstructsAction.cpp
diff --git a/tools/clang/plugins/FindBadConstructsAction.cpp b/tools/clang/plugins/FindBadConstructsAction.cpp
index ccf7f6397f256d0c5dab4199213b12e79f4c4b77..5667636f2707b40d485e24033d29b5ac194c5003 100644
--- a/tools/clang/plugins/FindBadConstructsAction.cpp
+++ b/tools/clang/plugins/FindBadConstructsAction.cpp
@@ -36,6 +36,8 @@ bool FindBadConstructsAction::ParseArgs(const CompilerInstance& instance,
       // TODO(tsepez): Enable this by default once http://crbug.com/356815
       // and http://crbug.com/356816 are fixed.
       options_.check_enum_last_value = true;
+    } else if (args[0] == "strict-virtual-annotations") {
+      options_.strict_virtual_annotations = true;
     } else {
       parsed = false;
       llvm::errs() << "Unknown clang plugin argument: " << args[i] << "\n";