Fix for crash found by IPC fuzzing.

content/browser/media/webrtc/webrtc_eventlog_host.cc

 // Copyright 2016 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 "content/browser/media/webrtc/webrtc_eventlog_host.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/files/file_util.h"
@@ skipping 60 matching lines @@
   if (webrtc_internals->IsEventLogRecordingsEnabled())
     StartWebRTCEventLog(webrtc_internals->GetEventLogFilePath());
 }
 
 WebRTCEventLogHost::~WebRTCEventLogHost() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 }
 
 void WebRTCEventLogHost::PeerConnectionAdded(int peer_connection_local_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  DCHECK(std::find(active_peer_connection_local_ids_.begin(),
-                   active_peer_connection_local_ids_.end(),
-                   peer_connection_local_id) ==
-         active_peer_connection_local_ids_.end());
-  active_peer_connection_local_ids_.push_back(peer_connection_local_id);
-  if (rtc_event_logging_enabled_ &&
-      number_active_log_files_ < kMaxNumberLogFiles) {
-    StartEventLogForPeerConnection(peer_connection_local_id);
+  if (std::find(active_peer_connection_local_ids_.begin(),
+                active_peer_connection_local_ids_.end(),
+                peer_connection_local_id) ==
+      active_peer_connection_local_ids_.end()) {
+    active_peer_connection_local_ids_.push_back(peer_connection_local_id);
+    if (rtc_event_logging_enabled_ &&
+        number_active_log_files_ < kMaxNumberLogFiles) {
+      StartEventLogForPeerConnection(peer_connection_local_id);
+    }
   }
 }
 
 void WebRTCEventLogHost::PeerConnectionRemoved(int peer_connection_local_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   const auto found = std::find(active_peer_connection_local_ids_.begin(),
                                active_peer_connection_local_ids_.end(),
                                peer_connection_local_id);
-  DCHECK(found != active_peer_connection_local_ids_.end());
-  active_peer_connection_local_ids_.erase(found);
+  if (found != active_peer_connection_local_ids_.end()) {
+    active_peer_connection_local_ids_.erase(found);
+  }
 }
 
 bool WebRTCEventLogHost::StartWebRTCEventLog(const base::FilePath& file_path) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (rtc_event_logging_enabled_)
     return false;
   rtc_event_logging_enabled_ = true;
   base_file_path_ = file_path;
   for (int local_id : active_peer_connection_local_ids_)
     StartEventLogForPeerConnection(local_id);
@@ skipping 39 matching lines @@
   if (rph) {
     rph->Send(new PeerConnectionTracker_StartEventLog(peer_connection_local_id,
                                                       file_for_transit));
   } else {
     --number_active_log_files_;
     IPC::PlatformFileForTransitToFile(file_for_transit).Close();
   }
 }
 
 }  // namespace content