Fix destruction order of PromoResourceService and NTPResourceCache

The existing code was leading to a crash:
- NTPResourceCache has a callback subscription on PromoResourceService
- PromoResourceService was deleted before NTPResourceCache
- When the NTPResourceCache was destroyed, it tried to remove itself
  from the callback list, which no longer exists and crashes.

The bug was introduced by
https://codereview.chromium.org/926633002

This CL changes the destruction order so that the PromoResourceService
is deleted after NTPResourceCache (which is a keyed service and thus is
tied to the profile).

BUG=464391

Review URL: https://codereview.chromium.org/988433002

Cr-Commit-Position: refs/heads/master@{#319491}

1 files changed, 100 insertions, 0 deletions

diff --git a/chrome/browser/browser_process_impl_unittest.cc b/chrome/browser/browser_process_impl_unittest.cc
new file mode 100644
index 0000000..2949c60
--- /dev/null
+++ b/chrome/browser/browser_process_impl_unittest.cc
@@ -0,0 +1,100 @@
+// 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 "chrome/browser/browser_process_impl.h"
+
+#include "base/command_line.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "base/thread_task_runner_handle.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/ui/webui/ntp/ntp_resource_cache_factory.h"
+#include "chrome/test/base/testing_profile.h"
+#include "content/public/test/test_browser_thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+class BrowserProcessImplTest : public ::testing::Test {
+ protected:
+  BrowserProcessImplTest()
+      : stashed_browser_process_(g_browser_process),
+        loop_(base::MessageLoop::TYPE_UI),
+        ui_thread_(content::BrowserThread::UI, &loop_),
+        file_thread_(
+            new content::TestBrowserThread(content::BrowserThread::FILE)),
+        io_thread_(new content::TestBrowserThread(content::BrowserThread::IO)),
+        command_line_(base::CommandLine::NO_PROGRAM),
+        browser_process_impl_(
+            new BrowserProcessImpl(base::ThreadTaskRunnerHandle::Get().get(),
+                                   command_line_)) {
+    browser_process_impl_->SetApplicationLocale("en");
+  }
+
+  ~BrowserProcessImplTest() override {
+    g_browser_process = nullptr;
+    browser_process_impl_.reset();
+    // Restore the original browser process.
+    g_browser_process = stashed_browser_process_;
+  }
+
+  // Creates the secondary threads (all threads except the UI thread).
+  // The UI thread needs to be alive while BrowserProcessImpl is alive, and is
+  // managed separately.
+  void StartSecondaryThreads() {
+    file_thread_->StartIOThread();
+    io_thread_->StartIOThread();
+  }
+
+  // Destroys the secondary threads (all threads except the UI thread).
+  // The UI thread needs to be alive while BrowserProcessImpl is alive, and is
+  // managed separately.
+  void DestroySecondaryThreads() {
+    // Spin the runloop to allow posted tasks to be processed.
+    base::RunLoop().RunUntilIdle();
+    io_thread_.reset();
+    base::RunLoop().RunUntilIdle();
+    file_thread_.reset();
+    base::RunLoop().RunUntilIdle();
+  }
+
+  BrowserProcessImpl* browser_process_impl() {
+    return browser_process_impl_.get();
+  }
+
+ private:
+  BrowserProcess* stashed_browser_process_;
+  base::MessageLoop loop_;
+  content::TestBrowserThread ui_thread_;
+  scoped_ptr<content::TestBrowserThread> file_thread_;
+  scoped_ptr<content::TestBrowserThread> io_thread_;
+  base::CommandLine command_line_;
+  scoped_ptr<BrowserProcessImpl> browser_process_impl_;
+};
+
+
+// Android does not have the NTPResourceCache.
+// This test crashes on ChromeOS because it relies on NetworkHandler which
+// cannot be used in test.
+#if !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
+TEST_F(BrowserProcessImplTest, LifeCycle) {
+  // Setup the BrowserProcessImpl and the threads.
+  browser_process_impl()->PreCreateThreads();
+  StartSecondaryThreads();
+  browser_process_impl()->PreMainMessageLoopRun();
+
+  // Force the creation of the NTPResourceCache, to test the destruction order.
+  scoped_ptr<Profile> profile(new TestingProfile);
+  NTPResourceCache* cache =
+      NTPResourceCacheFactory::GetForProfile(profile.get());
+  ASSERT_TRUE(cache);
+  // Pass ownership to the ProfileManager so that it manages the destruction.
+  browser_process_impl()->profile_manager()->RegisterTestingProfile(
+      profile.release(), false, false);
+
+  // Tear down the BrowserProcessImpl and the threads.
+  browser_process_impl()->StartTearDown();
+  DestroySecondaryThreads();
+  browser_process_impl()->PostDestroyThreads();
+}
+#endif  // !defined(OS_ANDROID) && !defined(OS_CHROMEOS)