Move isNearlyEmpty out into the ASTContext so it can be called from CodeGen as well.

llvm-svn: 120137
diff --git a/clang/lib/AST/CXXABI.h b/clang/lib/AST/CXXABI.h
index 5326cd4..943c43e 100644
--- a/clang/lib/AST/CXXABI.h
+++ b/clang/lib/AST/CXXABI.h
@@ -33,6 +33,10 @@
 
   /// Returns the default calling convention for C++ methods.
   virtual CallingConv getDefaultMethodCallConv() const = 0;
+
+  // Returns whether the given class is nearly empty, with just virtual pointers
+  // and no data except possibly virtual bases.
+  virtual bool isNearlyEmpty(const CXXRecordDecl *RD) const = 0;
 };
 
 /// Creates an instance of a C++ ABI class.