Use the tonic namespace for tonic + resulting build fixes

tonic/dart_gc_controller.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tonic/dart_gc_controller.h"
 
 #include "base/trace_event/trace_event.h"
 #include "dart/runtime/include/dart_api.h"
 #include "tonic/dart_gc_context.h"
 #include "tonic/dart_gc_visitor.h"
 #include "tonic/dart_wrappable.h"
 
-namespace blink {
+namespace tonic {
 namespace {
 
 DartGCContext* g_gc_context = nullptr;
 
 DartWrappable* GetWrappable(intptr_t* fields) {
   return reinterpret_cast<DartWrappable*>(fields[DartWrappable::kPeerIndex]);
 }
 
 void Visit(void* isolate_callback_data,
            Dart_WeakPersistentHandle handle,
@@ skipping 18 matching lines @@
 }
 
 void DartGCEpilogue() {
   delete g_gc_context;
   g_gc_context = nullptr;
   Dart_ExitScope();
 
   TRACE_EVENT_ASYNC_END0("sky", "DartGC", 0);
 }
 
-}  // namespace blink
+}  // namespace tonic