Oilpan: Replace EAGERLY_FINALIZE in EventTarget's hierarchy with pre-finalizers

third_party/WebKit/Source/modules/mediastream/RTCPeerConnection.cpp

Index: third_party/WebKit/Source/modules/mediastream/RTCPeerConnection.cpp
diff --git a/third_party/WebKit/Source/modules/mediastream/RTCPeerConnection.cpp b/third_party/WebKit/Source/modules/mediastream/RTCPeerConnection.cpp
index b77dd2f8ae5540744ef64cc33e49bd450fbe26e6..8bfd9bc601afb519021353d4d1e58b50ff8a0a77 100644
--- a/third_party/WebKit/Source/modules/mediastream/RTCPeerConnection.cpp
+++ b/third_party/WebKit/Source/modules/mediastream/RTCPeerConnection.cpp
@@ -413,6 +413,7 @@ RTCPeerConnection::RTCPeerConnection(ExecutionContext* context, RTCConfiguration
     , m_stopped(false)
     , m_closed(false)
 {
+    ThreadState::current()->registerPreFinalizer(this);
     Document* document = toDocument(getExecutionContext());
 
     // If we fail, set |m_closed| and |m_stopped| to true, to avoid hitting the assert in the destructor.
@@ -449,6 +450,13 @@ RTCPeerConnection::~RTCPeerConnection()
     DCHECK(m_closed || m_stopped);
 }
 
+void RTCPeerConnection::dispose()
+{
+    // Promptly clears a raw reference from content/ to an on-heap object
+    // so that content/ doesn't access it in a lazy sweeping phase.
+    m_peerHandler.clear();
+}
+
 ScriptPromise RTCPeerConnection::createOffer(ScriptState* scriptState, const RTCOfferOptions& options)
 {
     if (m_signalingState == SignalingStateClosed)