Revert "Make DestructorAtExit LazyInstances leak."

This reverts commit 1b97e93c.

Reason for revert: Speculative revert due to Linux TSAN unittest errors:
https://uberchromegw.corp.google.com/i/chromium.memory/builders/Linux%20TSan%20Tests/builds/17057

Original change's description:
> Make DestructorAtExit LazyInstances leak.
> 
> This means that tests may no longer rely on LazyInstance<T> to clean
> up global state between tests. Tests that depend on globals but need
> a clean test environment should use explicit test hooks to reset this
> state.
> 
> Only one test depends on DestructorAtExit for correct functionality.
> cast_audio_backend_unittests creates several mocks that are owned by a
> base::LazyInstance. Since Gmock verifies expectations in destructors,
> switching all LazyInstances to leaky ones breaks this verification.
> The solution is to manually verify and check the expectations at the
> end of the test.
> 
> Note that while the mock objects are annotated as leaked for Gmock,
> that does not mean the cast_audio_backend_unittests will leak
> arbitrary amounts of memory. The test fixture already configures
> StreamMixer for each test run; this setup will clear up any leftover
> objects from the previous test.
> 
> DestructorAtExit will be removed in a followup.
> 
> Bug: 698982
> Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
> Change-Id: I822ce507dbb98067a788466e7c8fcc96c3a64ef9
> Reviewed-on: https://chromium-review.googlesource.com/874994
> Commit-Queue: Daniel Cheng <dcheng@chromium.org>
> Reviewed-by: Kenneth MacKay <kmackay@chromium.org>
> Reviewed-by: Gabriel Charette <gab@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#531385}

TBR=dcheng@chromium.org,gab@chromium.org,kmackay@chromium.org

Change-Id: Ief1f9169caa0ff81e2c095df0a0520a71d7640a1
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 698982
Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Reviewed-on: https://chromium-review.googlesource.com/882506Reviewed-by: Joe Downing <joedow@chromium.org>
Commit-Queue: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#531398}

base/lazy_instance.h

@@ -81,6 +81,25 @@ struct LazyInstanceTraitsBase {
 // can implement the more complicated pieces out of line in the .cc file.
 namespace internal {
 
+// This traits class causes destruction the contained Type at process exit via
+// AtExitManager. This is probably generally not what you want. Instead, prefer
+// Leaky below.
+template <typename Type>
+struct DestructorAtExitLazyInstanceTraits {
+  static const bool kRegisterOnExit = true;
+#if DCHECK_IS_ON()
+  static const bool kAllowedToAccessOnNonjoinableThread = false;
+#endif
+
+  static Type* New(void* instance) {
+    return LazyInstanceTraitsBase<Type>::New(instance);
+  }
+
+  static void Delete(Type* instance) {
+    LazyInstanceTraitsBase<Type>::CallDestructor(instance);
+  }
+};
+
 // Use LazyInstance<T>::Leaky for a less-verbose call-site typedef; e.g.:
 // base::LazyInstance<T>::Leaky my_leaky_lazy_instance;
 // instead of:
@@ -104,11 +123,6 @@ struct LeakyLazyInstanceTraits {
   }
 };
 
-// TODO(dcheng): DestructorAtExit will be completely removed in followups if
-// there are no issues discovered.
-template <typename Type>
-using DestructorAtExitLazyInstanceTraits = LeakyLazyInstanceTraits<Type>;
-
 template <typename Type>
 struct ErrorMustSelectLazyOrDestructorAtExitForLazyInstance {};
 
@@ -133,10 +147,9 @@ class LazyInstance {
 
   // Convenience typedef to avoid having to repeat Type for leaky lazy
   // instances.
-  using Leaky = LazyInstance<Type, internal::LeakyLazyInstanceTraits<Type>>;
-  // TODO(dcheng): DestructorAtExit will be completely removed in followups if
-  // there are no issues discovered.
-  using DestructorAtExit = Leaky;
+  typedef LazyInstance<Type, internal::LeakyLazyInstanceTraits<Type>> Leaky;
+  typedef LazyInstance<Type, internal::DestructorAtExitLazyInstanceTraits<Type>>
+      DestructorAtExit;
 
   Type& Get() {
     return *Pointer();

chromecast/media/cma/backend/alsa/stream_mixer_unittest.cc

@@ -472,22 +472,7 @@ class StreamMixerTest : public testing::Test {
     StreamMixer::Get()->SetMixerOutputStreamForTest(std::move(output));
   }
 
-  ~StreamMixerTest() override {
-    // The remaining MockPostProcessor objects are still indirectly owned by a
-    // leaky static.  Manually verify and clear them here and mark them as
-    // leaked so Gmock doesn't complain.
-    for (auto& itr : *MockPostProcessor::instances()) {
-      testing::Mock::VerifyAndClear(itr.second);
-      testing::Mock::AllowLeak(itr.second);
-    }
-    MockPostProcessor::instances()->clear();
-
-    // Similarly, mock_alsa_ is also indirectly owned by a leaky static.
-    testing::Mock::VerifyAndClear(mock_alsa_);
-    testing::Mock::AllowLeak(mock_alsa_);
-
-    StreamMixer::Get()->ClearInputsForTest();
-  }
+  ~StreamMixerTest() override { StreamMixer::Get()->ClearInputsForTest(); }
 
   MockAlsaWrapper* mock_alsa() { return mock_alsa_; }