Move symbol table from per isolate snapshot to vm isolate snapshot, this reduces the per isolate in…

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, 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.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
@@ skipping 1407 matching lines @@
 
 
 DART_EXPORT Dart_Handle Dart_CreateSnapshot(
     uint8_t** vm_isolate_snapshot_buffer,
     intptr_t* vm_isolate_snapshot_size,
     uint8_t** isolate_snapshot_buffer,
     intptr_t* isolate_snapshot_size) {
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
   TIMERSCOPE(isolate, time_creating_snapshot);
-  if (vm_isolate_snapshot_buffer == NULL) {
-    RETURN_NULL_ERROR(vm_isolate_snapshot_buffer);
-  }
-  if (vm_isolate_snapshot_size == NULL) {
+  if (vm_isolate_snapshot_buffer != NULL &&
+      vm_isolate_snapshot_size == NULL) {
     RETURN_NULL_ERROR(vm_isolate_snapshot_size);
   }
   if (isolate_snapshot_buffer == NULL) {
     RETURN_NULL_ERROR(isolate_snapshot_buffer);
   }
   if (isolate_snapshot_size == NULL) {
     RETURN_NULL_ERROR(isolate_snapshot_size);
   }
   // Finalize all classes if needed.
   Dart_Handle state = Api::CheckAndFinalizePendingClasses(isolate);
@@ skipping 3627 matching lines @@
   }
   Library& library =
       Library::Handle(isolate, isolate->object_store()->root_library());
   if (!library.IsNull()) {
     const String& library_url = String::Handle(isolate, library.url());
     return Api::NewError("%s: A script has already been loaded from '%s'.",
                          CURRENT_FUNC, library_url.ToCString());
   }
   CHECK_CALLBACK_STATE(isolate);
 
-  SnapshotReader reader(snapshot->content(),
-                        snapshot->length(),
-                        snapshot->kind(),
-                        isolate,
-                        zone.GetZone());
+  ASSERT(snapshot->kind() == Snapshot::kScript);
+  ScriptSnapshotReader reader(snapshot->content(),
+                              snapshot->length(),
+                              isolate,
+                              zone.GetZone());
   const Object& tmp = Object::Handle(isolate, reader.ReadScriptSnapshot());
   if (tmp.IsError()) {
     return Api::NewHandle(isolate, tmp.raw());
   }
   library ^= tmp.raw();
   library.set_debuggable(true);
   isolate->object_store()->set_root_library(library);
   return Api::NewHandle(isolate, library.raw());
 }
 
@@ skipping 476 matching lines @@
 
 
 DART_EXPORT void Dart_RegisterRootServiceRequestCallback(
     const char* name,
     Dart_ServiceRequestCallback callback,
     void* user_data) {
   Service::RegisterRootEmbedderCallback(name, callback, user_data);
 }
 
 }  // namespace dart