Use the tonic namespace for tonic + resulting build fixes

tonic/dart_wrappable.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_wrappable.h"
 
 #include "tonic/dart_class_library.h"
 #include "tonic/dart_error.h"
 #include "tonic/dart_exception_factory.h"
 #include "tonic/dart_state.h"
 #include "tonic/dart_wrapper_info.h"
 
-namespace blink {
+namespace tonic {
 
 DartWrappable::~DartWrappable() {
   CHECK(!dart_wrapper_);
 }
 
 void DartWrappable::AcceptDartGCVisitor(DartGCVisitor& visitor) const {
 }
 
 Dart_Handle DartWrappable::CreateDartWrapper(DartState* dart_state) {
   DCHECK(!dart_wrapper_);
@@ skipping 83 matching lines @@
   Dart_Handle result = Dart_GetNativeFieldsOfArgument(
       args, index, DartWrappable::kNumberOfNativeFields, native_fields);
   if (Dart_IsError(result)) {
     exception = Dart_NewStringFromCString(DartError::kInvalidArgument);
     return nullptr;
   }
   return reinterpret_cast<DartWrappable*>(
       native_fields[DartWrappable::kPeerIndex]);
 }
 
-}  // namespace blink
+}  // namespace tonic