Reland: Fix crash when the source browser window is deleted during a drag

chrome/test/base/view_event_test_base.cc

 // Copyright (c) 2012 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 "chrome/test/base/view_event_test_base.h"
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "chrome/test/base/chrome_unit_test_suite.h"
 #include "chrome/test/base/interactive_test_utils.h"
@@ skipping 70 matching lines @@
   // The ContextFactory must exist before any Compositors are created.
   bool enable_pixel_output = false;
   ui::ContextFactory* context_factory =
       ui::InitializeContextFactoryForTests(enable_pixel_output);
   views_delegate_.set_context_factory(context_factory);
   views_delegate_.set_use_desktop_native_widgets(true);
 
   platform_part_.reset(ViewEventTestPlatformPart::Create(context_factory));
   gfx::NativeWindow context = platform_part_->GetContext();
   window_ = views::Widget::CreateWindowWithContext(this, context);
+  window_->Show();
 }
 
 void ViewEventTestBase::TearDown() {
   if (window_) {
     window_->Close();
     content::RunAllPendingInMessageLoop();
     window_ = NULL;
   }
 
   ui::Clipboard::DestroyClipboardForCurrentThread();
@@ skipping 67 matching lines @@
   dnd_thread_.reset(NULL);
 }
 
 void ViewEventTestBase::RunTestMethod(const base::Closure& task) {
   StopBackgroundThread();
 
   task.Run();
   if (HasFatalFailure())
     Done();
 }