Make --noopt behave like an in-place precompilation.

runtime/include/dart_api.h

 /*
  * 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.
  */
 
 #ifndef INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
@@ skipping 2859 matching lines @@
  */
 
 
 typedef struct {
   const char* library_uri;
   const char* class_name;
   const char* function_name;
 } Dart_QualifiedFunctionName;
 
 
+/**
+ * Compiles all functions reachable from the provided entry points and marks
+ * the isolate to disallow future compilation.
+ *
+ * \param entry_points A list of functions that may be invoked through the
+ * embedding API, e.g. Dart_Invoke/GetField/SetField/New/InvokeClosure.
+ *
+ * \param reset_fields Controls whether static fields are reset. Fields without
+ * an initializer will be set to null, and fields with an initializer will have
+ * their initializer run the next time they are accessed.
+ *
+ * reset_fields is true when we are about to create a precompilated snapshot.
+ * Some fields are already been initialized as part of the loading logic, and
+ * we want them to be reinitialized in the new process that will load the
+ * snapshot. reset_fields is false for --noopt, which will continue running in
+ * the same process.
+ *
+ * \return An error handle if a compilation error or runtime error running const
+ * constructors was encountered.
+ */
 DART_EXPORT Dart_Handle Dart_Precompile(
-    Dart_QualifiedFunctionName entry_points[]);
+    Dart_QualifiedFunctionName entry_points[],
+    bool reset_fields);
 
 
 DART_EXPORT Dart_Handle Dart_CreatePrecompiledSnapshot(
     uint8_t** vm_isolate_snapshot_buffer,
     intptr_t* vm_isolate_snapshot_size,
     uint8_t** isolate_snapshot_buffer,
     intptr_t* isolate_snapshot_size,
     uint8_t** instructions_snapshot_buffer,
     intptr_t* instructions_snapshot_size);
 
 #endif  /* INCLUDE_DART_API_H_ */  /* NOLINT */