Fix event tracing for windows test flakyness....

base/event_trace_controller_win.cc

 // Copyright (c) 2009 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.
 //
 // Implementation of a Windows event trace controller class.
 #include "base/event_trace_controller_win.h"
 #include "base/logging.h"
 
 EtwTraceController::EtwTraceController() : session_(NULL) {
 }
@@ skipping 79 matching lines @@
   ULONG error = ::ControlTrace(session_, NULL, properties->get(),
                                EVENT_TRACE_CONTROL_FLUSH);
   if (ERROR_SUCCESS != error)
     return HRESULT_FROM_WIN32(error);
 
   return S_OK;
 }
 
 HRESULT EtwTraceController::Start(const wchar_t* session_name,
     EtwTraceProperties* properties, TRACEHANDLE* session_handle) {
+  DCHECK(properties != NULL);
   ULONG err = ::StartTrace(session_handle, session_name, properties->get());
   return HRESULT_FROM_WIN32(err);
 }
 
 HRESULT EtwTraceController::Query(const wchar_t* session_name,
     EtwTraceProperties* properties) {
   ULONG err = ::ControlTrace(NULL, session_name, properties->get(),
                              EVENT_TRACE_CONTROL_QUERY);
   return HRESULT_FROM_WIN32(err);
 };
 
 HRESULT EtwTraceController::Update(const wchar_t* session_name,
     EtwTraceProperties* properties) {
+  DCHECK(properties != NULL);
   ULONG err = ::ControlTrace(NULL, session_name, properties->get(),
                              EVENT_TRACE_CONTROL_UPDATE);
   return HRESULT_FROM_WIN32(err);
 }
 
 HRESULT EtwTraceController::Stop(const wchar_t* session_name,
     EtwTraceProperties* properties) {
+  DCHECK(properties != NULL);
   ULONG err = ::ControlTrace(NULL, session_name, properties->get(),
                              EVENT_TRACE_CONTROL_STOP);
   return HRESULT_FROM_WIN32(err);
 }
 
 HRESULT EtwTraceController::Flush(const wchar_t* session_name,
     EtwTraceProperties* properties) {
+  DCHECK(properties != NULL);
   ULONG err = ::ControlTrace(NULL, session_name, properties->get(),
                              EVENT_TRACE_CONTROL_FLUSH);
   return HRESULT_FROM_WIN32(err);
 }