diff -r 000000000000 -r 6474c204b198 security/sandbox/win/src/sidestep_resolver.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/security/sandbox/win/src/sidestep_resolver.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,73 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SANDBOX_SRC_SIDESTEP_RESOLVER_H__
+#define SANDBOX_SRC_SIDESTEP_RESOLVER_H__
+
+#include "base/basictypes.h"
+#include "sandbox/win/src/nt_internals.h"
+#include "sandbox/win/src/resolver.h"
+
+namespace sandbox {
+
+// This is the concrete resolver used to perform sidestep interceptions.
+class SidestepResolverThunk : public ResolverThunk {
+ public:
+  SidestepResolverThunk() {}
+  virtual ~SidestepResolverThunk() {}
+
+  // Implementation of Resolver::Setup.
+  virtual NTSTATUS Setup(const void* target_module,
+                         const void* interceptor_module,
+                         const char* target_name,
+                         const char* interceptor_name,
+                         const void* interceptor_entry_point,
+                         void* thunk_storage,
+                         size_t storage_bytes,
+                         size_t* storage_used);
+
+  // Implementation of Resolver::GetThunkSize.
+  virtual size_t GetThunkSize() const;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SidestepResolverThunk);
+};
+
+// This is the concrete resolver used to perform smart sidestep interceptions.
+// This means basically a sidestep interception that skips the interceptor when
+// the caller resides on the same dll being intercepted. It is intended as
+// a helper only, because that determination is not infallible.
+class SmartSidestepResolverThunk : public SidestepResolverThunk {
+ public:
+  SmartSidestepResolverThunk() {}
+  virtual ~SmartSidestepResolverThunk() {}
+
+  // Implementation of Resolver::Setup.
+  virtual NTSTATUS Setup(const void* target_module,
+                         const void* interceptor_module,
+                         const char* target_name,
+                         const char* interceptor_name,
+                         const void* interceptor_entry_point,
+                         void* thunk_storage,
+                         size_t storage_bytes,
+                         size_t* storage_used);
+
+  // Implementation of Resolver::GetThunkSize.
+  virtual size_t GetThunkSize() const;
+
+ private:
+  // Performs the actual call to the interceptor if the conditions are correct
+  // (as determined by IsInternalCall).
+  static void SmartStub();
+
+  // Returns true if return_address is inside the module loaded at base.
+  static bool IsInternalCall(const void* base, void* return_address);
+
+  DISALLOW_COPY_AND_ASSIGN(SmartSidestepResolverThunk);
+};
+
+}  // namespace sandbox
+
+
+#endif  // SANDBOX_SRC_SIDESTEP_RESOLVER_H__