Fixing possible crash due to RefCountedChannel assignment operator.

webrtc/p2p/base/transportcontroller.h

Index: webrtc/p2p/base/transportcontroller.h
diff --git a/webrtc/p2p/base/transportcontroller.h b/webrtc/p2p/base/transportcontroller.h
index cdac4b6dcb5e72a08761a593b02d2f5fae9812c5..921d5508a110f0f1a87789273eaaef61fa936a98 100644
--- a/webrtc/p2p/base/transportcontroller.h
+++ b/webrtc/p2p/base/transportcontroller.h
@@ -17,6 +17,7 @@
 #include <vector>
 
 #include "webrtc/base/asyncinvoker.h"
+#include "webrtc/base/constructormagic.h"
 #include "webrtc/base/sigslot.h"
 #include "webrtc/base/sslstreamadapter.h"
 #include "webrtc/p2p/base/candidate.h"
@@ -170,10 +171,21 @@ class TransportController : public sigslot::has_slots<>,
     // TODO(deadbeef): Change the types of |dtls| and |ice| to
     // DtlsTransportChannelWrapper and P2PTransportChannelWrapper,
     // once TransportChannelImpl is removed.
-    explicit RefCountedChannel(TransportChannelImpl* dtls,
-                               TransportChannelImpl* ice)
+    RefCountedChannel(TransportChannelImpl* dtls, TransportChannelImpl* ice)

[honghaiz3, 2016/12/13 19:02:20]

Why do we implement our custom RefCounted class instead of using the webrtc
template RefCountedObject?

[Taylor Brandstetter, 2016/12/13 22:42:36]

I think just because no one has bothered to change it. I guess it makes sense to
do that now, instead of adding more code to the old thing. See new patchset.

         : ice_(ice), dtls_(dtls), ref_(0) {}
 
+    // Move assignment operator and move constructor needed since this goes in
+    // a vector.
+    RefCountedChannel(RefCountedChannel&& o)
+        : ice_(std::move(o.ice_)), dtls_(std::move(o.dtls_)), ref_(o.ref_) {
+    }
+    void operator=(RefCountedChannel&& o) {
+      // Need to delete the DTLS channel first since it depends on ICE.

[honghaiz3, 2016/12/13 19:02:20]

I wonder if we can better solve the dependency by letting DTLS channel own the
ICE channel. I understand we may need to have direct access to the ICE channel
per the standard, but we can always provide the access via DTLS channel. If we
do so, we don't need this struct. 

[Taylor Brandstetter, 2016/12/13 22:42:36]

We can discuss that separately, but I don't want to do that just to fix this
bug.

+      dtls_ = std::move(o.dtls_);
+      ice_ = std::move(o.ice_);
+      ref_ = o.ref_;
+    }
+
     void AddRef() { ++ref_; }
     void DecRef() {
       ASSERT(ref_ > 0);
@@ -282,6 +294,8 @@ class TransportController : public sigslot::has_slots<>,
   bool quic_ = false;
 
   webrtc::MetricsObserverInterface* metrics_observer_ = nullptr;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(TransportController);
 };
 
 }  // namespace cricket