Make chrome_elf use thunks instead of function pointers.

sandbox/win/src/service_resolver.h

 // Copyright (c) 2012 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_SERVICE_RESOLVER_H__
 #define SANDBOX_SRC_SERVICE_RESOLVER_H__
 
 #include "sandbox/win/src/nt_internals.h"
 #include "sandbox/win/src/resolver.h"
 
@@ skipping 28 matching lines @@
   virtual NTSTATUS ResolveTarget(const void* module,
                                  const char* function_name,
                                  void** address);
 
   // Implementation of Resolver::GetThunkSize.
   virtual size_t GetThunkSize() const;
 
   // Call this to set up ntdll_base_ which will allow for local patches.
   virtual void AllowLocalPatches();
 
+  // Verify that the function specified by |target_name| in |target_module| is a
+  // service and copy the first |storage_bytes| of data from that function into
+  // |thunk_storage|.
+  virtual NTSTATUS CopyThunk(const void* target_module,
+                             const char* target_name,
+                             BYTE* thunk_storage,
+                             size_t storage_bytes,
+                             size_t* storage_used);
+
  protected:
   // The unit test will use this member to allow local patch on a buffer.
   HMODULE ntdll_base_;
 
   // Handle of the child process.
   HANDLE process_;
 
  protected:
   // Keeps track of a Windows 2000 resolver.
   bool win2k_;
@@ skipping 83 matching lines @@
  private:
   virtual bool IsFunctionAService(void* local_thunk) const;
 
   DISALLOW_COPY_AND_ASSIGN(Win8ResolverThunk);
 };
 
 }  // namespace sandbox
 
 
 #endif  // SANDBOX_SRC_SERVICE_RESOLVER_H__