Add empty dart:platform library.

runtime/vm/object_store.h

Index: runtime/vm/object_store.h
diff --git a/runtime/vm/object_store.h b/runtime/vm/object_store.h
index 6ccdff9aa5547a1850eacce76868127b7082f625..b3e84fa7b92a9100d7d70dc3cbd16b1d5d46a41f 100644
--- a/runtime/vm/object_store.h
+++ b/runtime/vm/object_store.h
@@ -30,6 +30,7 @@ class ObjectStore {
     kJson,
     kMath,
     kMirrors,
+    kPlatform,
     kTypedData,
     kUtf,
   };
@@ -280,6 +281,7 @@ class ObjectStore {
   RawLibrary* json_library() const { return json_library_; }
   RawLibrary* math_library() const { return math_library_; }
   RawLibrary* mirrors_library() const { return mirrors_library_; }
+  RawLibrary* platform_library() const { return platform_library_; }
   RawLibrary* typed_data_library() const { return typed_data_library_; }
   RawLibrary* utf_library() const { return utf_library_; }
   void set_bootstrap_library(intptr_t index, const Library& value) {
@@ -311,6 +313,9 @@ class ObjectStore {
       case kMirrors:
         mirrors_library_ = value.raw();
         break;
+      case kPlatform:
+        platform_library_ = value.raw();
+        break;
       case kTypedData:
         typed_data_library_ = value.raw();
         break;
@@ -484,6 +489,7 @@ class ObjectStore {
   RawLibrary* math_library_;
   RawLibrary* mirrors_library_;
   RawLibrary* native_wrappers_library_;
+  RawLibrary* platform_library_;
   RawLibrary* root_library_;
   RawLibrary* typed_data_library_;
   RawLibrary* utf_library_;