Add a stubbed-out implementation of FlowGraphCompiler for ia32 and arm.

runtime/vm/code_generator_ia32.h

Index: runtime/vm/code_generator_ia32.h
diff --git a/runtime/vm/code_generator_ia32.h b/runtime/vm/code_generator_ia32.h
index 1237ca89073b03b61aacf7e9e8d4adc0f4b52b14..eeb5ff336e61023b0fd8403c28364faa43ee48aa 100644
--- a/runtime/vm/code_generator_ia32.h
+++ b/runtime/vm/code_generator_ia32.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -107,6 +107,9 @@ NODE_LIST(DEFINE_VISITOR_FUNCTION)
 
   // Add pc descriptors to code.
   void FinalizePcDescriptors(const Code& code);
+  // Verify assumptions about pc descriptors in debug mode.
+  static void VerifyPcDescriptors(const PcDescriptors& descriptors,
+                                  bool check_ids);
 
   // Add local variable descriptors to code.
   void FinalizeVarDescriptors(const Code& code);