[tracing] Allow asynchronous unregistration of unbound dump providers

base/trace_event/memory_dump_manager_unittest.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 "base/trace_event/memory_dump_manager.h"
 
 #include "base/bind_helpers.h"
 #include "base/memory/scoped_vector.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
@@ skipping 184 matching lines @@
   for (int i = 0; i < 3; ++i)
     RequestGlobalDumpAndWait(MemoryDumpType::EXPLICITLY_TRIGGERED,
                              MemoryDumpLevelOfDetail::DETAILED);
   DisableTracing();
 
   mdm_->UnregisterDumpProvider(&mdp);
 
   // Finally check the unregister logic: the delegate will be invoked but not
   // the dump provider, as it has been unregistered.
   EnableTracingWithLegacyCategories(MemoryDumpManager::kTraceCategory);
-  EXPECT_CALL(*delegate_, RequestGlobalMemoryDump(_, _)).Times(1);
+  EXPECT_CALL(*delegate_, RequestGlobalMemoryDump(_, _)).Times(3);
   EXPECT_CALL(mdp, OnMemoryDump(_, _)).Times(0);
-  RequestGlobalDumpAndWait(MemoryDumpType::EXPLICITLY_TRIGGERED,
-                           MemoryDumpLevelOfDetail::DETAILED);
+
+  for (int i = 0; i < 3; ++i) {
+    RequestGlobalDumpAndWait(MemoryDumpType::EXPLICITLY_TRIGGERED,
+                             MemoryDumpLevelOfDetail::DETAILED);
+  }
   DisableTracing();
 }
 
 // Checks that requesting dumps with high level of detail actually propagates
 // the level of the detail properly to OnMemoryDump() call on dump providers.
 TEST_F(MemoryDumpManagerTest, CheckMemoryDumpArgs) {
   InitializeMemoryDumpManager(false /* is_coordinator */);
   MockMemoryDumpProvider mdp;
 
   RegisterDumpProvider(&mdp);
@@ skipping 350 matching lines @@
   EnableTracingWithLegacyCategories(MemoryDumpManager::kTraceCategory);
   EXPECT_CALL(*delegate_, RequestGlobalMemoryDump(_, _)).Times(1);
   RequestGlobalDumpAndWait(MemoryDumpType::EXPLICITLY_TRIGGERED,
                            MemoryDumpLevelOfDetail::DETAILED);
   ASSERT_EQ(1, on_memory_dump_call_count);
   ASSERT_EQ(true, last_callback_success_);
 
   DisableTracing();
 }
 
+// If a thread (with a dump provider living on it) is torn down during a dump
+// its dump provider should be skipped but the dump itself shall succeed.
+TEST_F(MemoryDumpManagerTest, TearDownThreadWhileDumping) {
+  InitializeMemoryDumpManager(false /* is_coordinator */);
+  ScopedVector<TestIOThread> threads;

[Ruud van Asseldonk, 2015/12/14 16:25:49]

Scoped vectors are being removed in favour of |std::vector<scoped_ptr<T>>|.

+  ScopedVector<MockMemoryDumpProvider> mdps;
+
+  for (int i = 0; i < 2; i++) {
+    threads.push_back(new TestIOThread(TestIOThread::kAutoStart));
+    mdps.push_back(new MockMemoryDumpProvider());
+    RegisterDumpProvider(mdps.back(), threads.back()->task_runner(),
+                         kDefaultOptions);
+  }
+
+  int on_memory_dump_call_count = 0;
+
+  // When OnMemoryDump is called on either of the dump providers, it will
+  // tear down the thread of the other one.
+  for (MockMemoryDumpProvider* mdp : mdps) {
+    int other_idx = (mdps.front() == mdp);
+    TestIOThread* other_thread = threads[other_idx];
+    auto on_dump = [other_thread, &on_memory_dump_call_count](
+        const MemoryDumpArgs& args, ProcessMemoryDump* pmd) {
+      other_thread->Stop();
+      on_memory_dump_call_count++;
+      return true;
+    };
+
+    // OnMemoryDump is called once for the provider that dumps first, and zero
+    // times for the other provider.
+    EXPECT_CALL(*mdp, OnMemoryDump(_, _))
+        .Times(AtMost(1))
+        .WillOnce(Invoke(on_dump));
+  }
+
+  last_callback_success_ = false;
+  EnableTracingWithLegacyCategories(MemoryDumpManager::kTraceCategory);
+  EXPECT_CALL(*delegate_, RequestGlobalMemoryDump(_, _)).Times(1);
+  RequestGlobalDumpAndWait(MemoryDumpType::EXPLICITLY_TRIGGERED,
+                           MemoryDumpLevelOfDetail::DETAILED);
+  ASSERT_EQ(1, on_memory_dump_call_count);
+  ASSERT_EQ(true, last_callback_success_);
+
+  DisableTracing();
+}
+
 // Checks that a NACK callback is invoked if RequestGlobalDump() is called when
 // tracing is not enabled.
 TEST_F(MemoryDumpManagerTest, CallbackCalledOnFailure) {
   InitializeMemoryDumpManager(false /* is_coordinator */);
   MockMemoryDumpProvider mdp1;
   RegisterDumpProvider(&mdp1);
 
   EXPECT_CALL(*delegate_, RequestGlobalMemoryDump(_, _)).Times(0);
   EXPECT_CALL(mdp1, OnMemoryDump(_, _)).Times(0);
 
@@ skipping 165 matching lines @@
   RunLoop run_loop;
   MemoryDumpCallback callback =
       Bind(&MemoryDumpManagerTest::DumpCallbackAdapter, Unretained(this),
            MessageLoop::current()->task_runner(), run_loop.QuitClosure());
   mdm_->RequestGlobalDump(MemoryDumpType::EXPLICITLY_TRIGGERED,
                           MemoryDumpLevelOfDetail::DETAILED, callback);
   DisableTracing();
   tracing_disabled_event.Signal();
   run_loop.Run();
 
-  // RequestGlobalMemoryDump() should be NACK-ed because one of the threads
-  // threads died before we had a chance to PostTask onto them.
-  EXPECT_FALSE(last_callback_success_);
+  // RequestGlobalMemoryDump() should still suceed even if some threads were
+  // torn down during the dump.
+  EXPECT_TRUE(last_callback_success_);
 }
 
 TEST_F(MemoryDumpManagerTest, DumpOnBehalfOfOtherProcess) {
   using trace_analyzer::Query;
 
   InitializeMemoryDumpManager(false /* is_coordinator */);
 
   // Standard provider with default options (create dump for current process).
   MemoryDumpProvider::Options options;
   MockMemoryDumpProvider mdp1;
@@ skipping 40 matching lines @@
   ASSERT_EQ(1u, trace_analyzer::CountMatches(events, Query::EventPidIs(123)));
   ASSERT_EQ(1u, trace_analyzer::CountMatches(events, Query::EventPidIs(456)));
   ASSERT_EQ(1u, trace_analyzer::CountMatches(
                     events, Query::EventPidIs(GetCurrentProcId())));
   ASSERT_EQ(events[0]->id, events[1]->id);
   ASSERT_EQ(events[0]->id, events[2]->id);
 }
 
 }  // namespace trace_event
 }  // namespace base