Fix TestBrowserThread destruction order in CrOS tests.

chrome/browser/metrics/leak_detector/leak_detector_controller_unittest.cc

 // Copyright 2016 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/metrics/leak_detector/leak_detector_controller.h"
 
 #include <set>
 
 #include "base/lazy_instance.h"
 #include "base/macros.h"
@@ skipping 38 matching lines @@
   // For supporting content::BrowserThread operations.
   content::TestBrowserThreadBundle thread_bundle_;
 
   DISALLOW_COPY_AND_ASSIGN(LeakDetectorControllerTest);
 };
 
 // Use a global instance of the test class because LeakDetectorController
 // initializes class LeakDetector, which can only be initialized once, enforced
 // by an internal CHECK. Multiple initializations of LeakDetectorController in
 // the same process will result in multiple initializations of class
-// LeakDetector.
+// LeakDetector. It has to be Leaky as running its destructor will otherwise
+// DCHECK when called outside the scope of a TestBrowserThreadBundle.
 //
 // See src/components/metrics/leak_detector/leak_detector.h for more info.
-base::LazyInstance<TestLeakDetectorController> g_instance =
+base::LazyInstance<TestLeakDetectorController>::Leaky g_instance =
     LAZY_INSTANCE_INITIALIZER;
 
 TEST_F(LeakDetectorControllerTest, SingleReport) {
   MemoryLeakReportProto report;
   report.set_size_bytes(8);
   InitializeRepeatedField({1, 2, 3, 4}, report.mutable_call_stack());
 
   TestLeakDetectorController* controller = &g_instance.Get();
   controller->OnLeaksFound({report});
 
@@ skipping 187 matching lines @@
   EXPECT_EQ(13U, stored_reports[2].call_stack().Get(4));
   EXPECT_EQ(14U, stored_reports[2].call_stack().Get(5));
   EXPECT_EQ(15U, stored_reports[2].call_stack().Get(6));
   EXPECT_EQ(16U, stored_reports[2].call_stack().Get(7));
 
   controller->GetLeakReports(&stored_reports);
   ASSERT_EQ(0U, stored_reports.size());
 }
 
 }  // namespace metrics