Fix windows build errors.

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, 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 "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "lib/stacktrace.h"
 #include "platform/assert.h"
@@ skipping 5099 matching lines @@
   CHECK_COMPILATION_ALLOWED(I);
 
   Dart_Handle result;
 #if !defined(DART_PRECOMPILED_RUNTIME)
   if (FLAG_use_dart_frontend && !KernelIsolate::IsKernelIsolate(I)) {
     if ((source == Api::Null()) || (source == NULL)) {
       RETURN_NULL_ERROR(source);
     }
     void* kernel_pgm = reinterpret_cast<void*>(source);
     result = LoadKernelProgram(T, resolved_url_str, kernel_pgm);
-    if (Dart_IsError(result)) {
+    if (::Dart_IsError(result)) {
       return result;
     }
     library ^= Library::LookupLibrary(T, resolved_url_str);
     if (library.IsNull()) {
       return Api::NewError("%s: Unable to load script '%s' correctly.",
                            CURRENT_FUNC, resolved_url_str.ToCString());
     }
     I->object_store()->set_root_library(library);
     return Api::NewHandle(T, library.raw());
   }
@@ skipping 332 matching lines @@
   if (url_str.IsNull()) {
     RETURN_TYPE_ERROR(Z, url, String);
   }
   Dart_Handle result;
 #if !defined(DART_PRECOMPILED_RUNTIME)
   // Kernel isolate is loaded from script in case of dart_bootstrap
   // even when FLAG_use_dart_frontend is true. Hence, do not interpret
   // |source| as a kernel if the current isolate is the kernel isolate.
   if (FLAG_use_dart_frontend && !KernelIsolate::IsKernelIsolate(I)) {
     result = LoadKernelProgram(T, url_str, reinterpret_cast<void*>(source));
-    if (Dart_IsError(result)) {
+    if (::Dart_IsError(result)) {
       return result;
     }
     return Api::NewHandle(T, Library::LookupLibrary(T, url_str));
   }
 #endif
   if (::Dart_IsNull(resolved_url)) {
     resolved_url = url;
   }
   const String& resolved_url_str = Api::UnwrapStringHandle(Z, resolved_url);
   if (resolved_url_str.IsNull()) {
@@ skipping 1262 matching lines @@
 #endif
 }
 
 DART_EXPORT void Dart_DumpNativeStackTrace(void* context) {
 #ifndef PRODUCT
   Profiler::DumpStackTrace(context);
 #endif
 }
 
 }  // namespace dart