Make chrome_elf use thunks instead of function pointers.

sandbox/win/src/service_resolver.h

Index: sandbox/win/src/service_resolver.h
diff --git a/sandbox/win/src/service_resolver.h b/sandbox/win/src/service_resolver.h
index 00896922049ad45b569a111f97384cb97f57782b..227f90c905c55a5f4cb288cc047fd451368f93eb 100644
--- a/sandbox/win/src/service_resolver.h
+++ b/sandbox/win/src/service_resolver.h
@@ -46,6 +46,15 @@ class ServiceResolverThunk : public ResolverThunk {
   // 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,
+                             void* 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_;