Destroy bound callback to BindToCurrentLoop on the target task runner (2)

media/base/bind_to_current_loop_unittest.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 "media/base/bind_to_current_loop.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/memory/free_deleter.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/synchronization/waitable_event.h"
+#include "base/threading/thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media {
 
 void BoundBoolSet(bool* var, bool val) {
   *var = val;
 }
 
 void BoundBoolSetFromScopedPtr(bool* var, std::unique_ptr<bool> val) {
   *var = *val;
@@ skipping 11 matching lines @@
 
 void BoundBoolSetFromConstRef(bool* var, const bool& val) {
   *var = val;
 }
 
 void BoundIntegersSet(int* a_var, int* b_var, int a_val, int b_val) {
   *a_var = a_val;
   *b_var = b_val;
 }
 
+struct ThreadRestrictionChecker {
+  ThreadRestrictionChecker() : bound_loop_(base::MessageLoop::current()) {}
+
+  void Run() { EXPECT_EQ(bound_loop_, base::MessageLoop::current()); }
+
+  ~ThreadRestrictionChecker() {
+    EXPECT_EQ(bound_loop_, base::MessageLoop::current());
+  }
+
+  base::MessageLoop* bound_loop_;
+};
+
+void RunAndClearReference(base::Closure cb) {
+  cb.Run();
+}
+
+void ClearReference(base::Closure cb) {}
+
 // Various tests that check that the bound function is only actually executed
 // on the message loop, not during the original Run.
 class BindToCurrentLoopTest : public ::testing::Test {
  protected:
   base::MessageLoop loop_;
 };
 
 TEST_F(BindToCurrentLoopTest, Closure) {
   // Test the closure is run inside the loop, not outside it.
   base::WaitableEvent waiter(base::WaitableEvent::ResetPolicy::AUTOMATIC,
@@ skipping 109 matching lines @@
   base::Callback<void(int, int)> cb = BindToCurrentLoop(base::Bind(
       &BoundIntegersSet, &a, &b));
   cb.Run(1, -1);
   EXPECT_EQ(a, 0);
   EXPECT_EQ(b, 0);
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(a, 1);
   EXPECT_EQ(b, -1);
 }
 
+TEST_F(BindToCurrentLoopTest, DestroyedOnBoundLoop) {
+  base::Thread target_thread("testing");
+  ASSERT_TRUE(target_thread.Start());
+
+  // Ensure that the bound object is also destroyed on the correct thread even
+  // if the last reference to the callback is dropped on the other thread.
+  // TODO(tzik): Remove RunAndClearReference once TaskRunner migrates to
+  // OnceClosure. RunAndCleareReference is needed to ensure no reference to |cb|
+  // is left to the original thread.
+  base::Closure cb = BindToCurrentLoop(
+      base::Bind(&ThreadRestrictionChecker::Run,
+                 base::MakeUnique<ThreadRestrictionChecker>()));
+  target_thread.task_runner()->PostTask(
+      FROM_HERE, base::Bind(&RunAndClearReference, base::Passed(&cb)));
+  ASSERT_FALSE(cb);
+  target_thread.FlushForTesting();
+  base::RunLoop().RunUntilIdle();
+
+  // Ensure that the bound object is destroyed on the target thread even if
+  // the callback is destroyed without invocation.
+  cb = BindToCurrentLoop(
+      base::Bind(&ThreadRestrictionChecker::Run,
+                 base::MakeUnique<ThreadRestrictionChecker>()));
+  target_thread.task_runner()->PostTask(
+      FROM_HERE, base::Bind(&ClearReference, base::Passed(&cb)));
+  target_thread.FlushForTesting();
+  ASSERT_FALSE(cb);
+  base::RunLoop().RunUntilIdle();
+
+  target_thread.Stop();
+}
+
 }  // namespace media