Remove 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 d131951801aa80afaf4792e03f2809809ccbb690..37add484c0b05630629c617e01d0bc95ac5dac80 100644
--- a/runtime/vm/object_store.h
+++ b/runtime/vm/object_store.h
@@ -29,7 +29,6 @@ class ObjectStore {
     kIsolate,
     kMath,
     kMirrors,
-    kPlatform,
     kTypedData,
     kUtf,
   };
@@ -279,7 +278,6 @@ class ObjectStore {
   RawLibrary* isolate_library() const { return isolate_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(BootstrapLibraryId index, const Library& value) {
@@ -308,9 +306,6 @@ class ObjectStore {
       case kMirrors:
         mirrors_library_ = value.raw();
         break;
-      case kPlatform:
-        platform_library_ = value.raw();
-        break;
       case kTypedData:
         typed_data_library_ = value.raw();
         break;
@@ -483,7 +478,6 @@ 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_;