Make tests/clipping/canvas-rounded-corners.sky actually run.

sky/engine/core/script/dart_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 "sky/engine/config.h"
 #include "sky/engine/core/script/dart_controller.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 82 matching lines @@
     dart_state()->loader().WaitForDependencies(
         dependencies, base::Bind(&DartController::ExecuteModule,
                                  weak_factory_.GetWeakPtr(), module));
   }
 }
 
 void DartController::ExecuteModule(RefPtr<AbstractModule> module) {
   DCHECK(Dart_CurrentIsolate() == dart_state()->isolate());
   DartApiScope dart_api_scope;
 
-  LogIfError(Dart_FinalizeLoading(true));
+  // Don't continue if we failed to load the module.
+  if (LogIfError(Dart_FinalizeLoading(true)))
+    return;
   Dart_Handle library = module->library()->dart_value();
   const char* name = module->isApplication() ? "main" : "init";
   Dart_Handle closure_name = Dart_NewStringFromCString(name);
   Dart_Handle result = Dart_Invoke(library, closure_name, 0, nullptr);
 
   if (module->isApplication()) {
     // TODO(dart): This will throw an API error if main() is absent. It would be
     // better to test whether main() is present first, then attempt to invoke it
     // so as to capture & report other errors.
     LogIfError(result);
@@ skipping 147 matching lines @@
 
   CHECK(Dart_SetVMFlags(argc, argv));
   CHECK(Dart_Initialize(IsolateCreateCallback,
                         nullptr,  // Isolate interrupt callback.
                         UnhandledExceptionCallback, IsolateShutdownCallback,
                         // File IO callbacks.
                         nullptr, nullptr, nullptr, nullptr, nullptr));
 }
 
 } // namespace blink