Do not qualify with dart:: except where necessary

runtime/vm/bootstrap_nocore.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/bootstrap.h"
 
 #include "include/dart_api.h"
 
 #if !defined(DART_PRECOMPILED_RUNTIME)
 #include "vm/class_finalizer.h"
@@ skipping 58 matching lines @@
 }
 
 RawError* BootstrapFromKernel(Thread* thread, kernel::Program* program) {
   Zone* zone = thread->zone();
   kernel::KernelReader reader(program);
   Isolate* isolate = thread->isolate();
   // Mark the already-pending classes.  This mark bit will be used to avoid
   // adding classes to the list more than once.
   GrowableObjectArray& pending_classes = GrowableObjectArray::Handle(
       zone, isolate->object_store()->pending_classes());
-  dart::Class& pending = dart::Class::Handle(zone);
+  Class& pending = Class::Handle(zone);
   for (intptr_t i = 0; i < pending_classes.Length(); ++i) {
     pending ^= pending_classes.At(i);
     pending.set_is_marked_for_parsing();
   }
 
   // Load the bootstrap libraries in order (see object_store.h).
   Library& library = Library::Handle(zone);
   String& dart_name = String::Handle(zone);
   for (intptr_t i = 0; i < bootstrap_library_count; ++i) {
     ObjectStore::BootstrapLibraryId id = bootstrap_libraries[i].index;
@@ skipping 50 matching lines @@
   return BootstrapFromKernel(thread, program);
 }
 #else
 RawError* Bootstrap::DoBootstrapping(kernel::Program* program) {
   UNREACHABLE();
   return Error::null();
 }
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)
 
 }  // namespace dart