Eliminate video capture thread in renderer

content/renderer/media/video_capture_impl_manager_unittest.cc

 // Copyright 2014 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/bind.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "content/child/child_process.h"
 #include "content/renderer/media/video_capture_impl.h"
@@ skipping 122 matching lines @@
 
     EXPECT_CALL(*client1, OnStopped(_));
     EXPECT_CALL(*client1, OnRemoved(_));
     EXPECT_CALL(*client2, OnStopped(_));
     EXPECT_CALL(*client2, OnRemoved(_)).WillOnce(
         RunClosure(quit_closure));
     handle1->StopCapture(client1.get());
     handle2->StopCapture(client2.get());
     run_loop.Run();
   }
+  EXPECT_TRUE(device1 == device2);
 
-  EXPECT_TRUE(device1 == device2);
   EXPECT_CALL(*static_cast<MockVideoCaptureImpl*>(device1), Destruct());
+
+  // We have to wait until MockVideoCaptureImpl is destroyed. Because we
+  // use gmock to expect destruction to happen. Otherwise TSAN will
+  // complain. This unfortunately means that we have to know the
+  // destruction sequence of VideoCaptureImpl.

[Ami GONE FROM CHROMIUM, 2014/01/13 18:26:37]

If the thing you're trying to assert here is that resetting the handles triggers
the device destructor then I think you can avoid the knowledge of dtor sequence
by giving the MockVideoCaptureImpl a set_dtor_cb method which would accept a
Closure and run it in the dtor, and then here replace l.145-168 with:
base::RunLoop run_loop;
device1.set_dtor_cb(run_loop.QuitClosure());
handle1.reset();
handle2.reset();
run_loop.Run();

No?

+
+  {
+    // Make sure there's no more task on the main thread.
+    // Destruction is now posted on the IO thread.
+    base::RunLoop run_loop;
+    handle1.reset();
+    handle2.reset();
+    run_loop.RunUntilIdle();
+  }
+  {
+    // Make sure there's no more task on the IO thread.
+    // VideoCaptureImpl is now destroyed.
+    base::RunLoop run_loop;
+    child_process_->io_message_loop_proxy()->PostTask(
+        FROM_HERE,
+        BindToCurrentLoop(run_loop.QuitClosure()));
+    run_loop.Run();
+  }
 }
 
 }  // namespace content