Refactor 'dart:profiler' UserTag API

runtime/vm/object.cc

 // 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 18648 matching lines @@
 }
 
 
 void UserTag::MakeActive() const {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   isolate->set_current_tag(*this);
 }
 
 
-void UserTag::ClearActive() {
-  Isolate* isolate = Isolate::Current();
-  ASSERT(isolate != NULL);
-  isolate->clear_current_tag();
-}
-
-
 RawUserTag* UserTag::New(const String& label, Heap::Space space) {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate->tag_table() != GrowableObjectArray::null());
   // Canonicalize by name.
   UserTag& result = UserTag::Handle(FindTagInIsolate(isolate, label));
   if (!result.IsNull()) {
     // Tag already exists, return existing instance.
     return result.raw();
   }
   if (TagTableIsFull(isolate)) {
@@ skipping 11 matching lines @@
                                       space);
     NoGCScope no_gc;
     result ^= raw;
   }
   result.set_label(label);
   AddTagToIsolate(isolate, result);
   return result.raw();
 }
 
 
+RawUserTag* UserTag::DefaultTag() {
+  Isolate* isolate = Isolate::Current();
+  ASSERT(isolate != NULL);
+  ASSERT(isolate->object_store() != NULL);
+  if (isolate->object_store()->default_tag() != UserTag::null()) {
+    // Already created.
+    return isolate->object_store()->default_tag();
+  }
+  // Create default tag.
+  const UserTag& result = UserTag::Handle(isolate,
+                                          UserTag::New(Symbols::Default()));
+  ASSERT(result.tag() == UserTags::kDefaultUserTag);
+  isolate->object_store()->set_default_tag(result);
+  return result.raw();
+}
+
+
 RawUserTag* UserTag::FindTagInIsolate(Isolate* isolate, const String& label) {
   ASSERT(isolate->tag_table() != GrowableObjectArray::null());
   const GrowableObjectArray& tag_table = GrowableObjectArray::Handle(
       isolate, isolate->tag_table());
   UserTag& other = UserTag::Handle(isolate);
   String& tag_label = String::Handle(isolate);
   for (intptr_t i = 0; i < tag_table.Length(); i++) {
     other ^= tag_table.At(i);
     ASSERT(!other.IsNull());
     tag_label ^= other.label();
@@ skipping 60 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart