Move the Compiler to CompilerDriver.

Change-Id: I0bb4d3c2b79b45fd8ef180688c767712b0c55978
diff --git a/src/compiler/dex/frontend.h b/src/compiler/dex/frontend.h
index f3e38c2..4e65d12 100644
--- a/src/compiler/dex/frontend.h
+++ b/src/compiler/dex/frontend.h
@@ -141,7 +141,7 @@
 
 }  // namespace art
 
-extern "C" art::CompiledMethod* ArtCompileMethod(art::Compiler& compiler,
+extern "C" art::CompiledMethod* ArtCompileMethod(art::CompilerDriver& driver,
                                                  const art::DexFile::CodeItem* code_item,
                                                  uint32_t access_flags,
                                                  art::InvokeType invoke_type,