Update NetLog to be thread safe.

chrome/browser/resources/net_internals/main.js

Index: chrome/browser/resources/net_internals/main.js
===================================================================
--- chrome/browser/resources/net_internals/main.js	(revision 67848)
+++ chrome/browser/resources/net_internals/main.js	(working copy)
@@ -308,9 +308,6 @@
 //------------------------------------------------------------------------------
 
 BrowserBridge.prototype.receivedLogEntry = function(logEntry) {
-  // Silently drop entries received before ready to receive them.
-  if (!this.areLogTypesReady_())
-    return;
   // Assign unique ID, if needed.
   if (logEntry.source.id == 0) {
     logEntry.source.id = this.nextSourcelessEventId_;
@@ -388,12 +385,27 @@
 };
 
 BrowserBridge.prototype.receivedPassiveLogEntries = function(entries) {
-  this.numPassivelyCapturedEvents_ += entries.length;
+  // Due to an expected race condition, it is possible to receive actively
+  // captured log entries before the passively logged entries are received.
+  //
+  // When that happens, we create a copy of the actively logged entries, delete
+  // all entries, and, after handling all the passively logged entries, add back
+  // the deleted actively logged entries.
+  var earlyActivelyCapturedEvents = this.capturedEvents_.slice(0);
+  if (earlyActivelyCapturedEvents.length > 0)
+    this.deleteAllEvents();
+
+  this.numPassivelyCapturedEvents_ = entries.length;
   for (var i = 0; i < entries.length; ++i) {
     var entry = entries[i];
     entry.wasPassivelyCaptured = true;
     this.receivedLogEntry(entry);
   }
+
+  // Add back early actively captured events, if any.
+  for (var i = 0; i < earlyActivelyCapturedEvents.length; ++i) {
+    this.receivedLogEntry(earlyActivelyCapturedEvents[i]);
+  }
 };
 
 
@@ -427,12 +439,6 @@
   this.pollableDataHelpers_.httpCacheInfo.update(info);
 };
 
-BrowserBridge.prototype.areLogTypesReady_ = function() {
-  return (LogEventType  != null &&
-          LogEventPhase != null &&
-          LogSourceType != null);
-};
-
 //------------------------------------------------------------------------------
 
 /**