base: Remove the string logging from CHECK().

ui/events/platform/platform_event_source.cc

 // Copyright 2014 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 "ui/events/platform/platform_event_source.h"
 
 #include <algorithm>
 
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "ui/events/platform/platform_event_dispatcher.h"
 #include "ui/events/platform/platform_event_observer.h"
 #include "ui/events/platform/scoped_event_dispatcher.h"
 
 namespace ui {
 
 // static
 PlatformEventSource* PlatformEventSource::instance_ = NULL;
 
 PlatformEventSource::PlatformEventSource()
     : overridden_dispatcher_(NULL),
       overridden_dispatcher_restored_(false) {
-  CHECK(!instance_) << "Only one platform event source can be created.";
+  // Only one platform event source can be created.
+  CHECK(!instance_);
   instance_ = this;
 }
 
 PlatformEventSource::~PlatformEventSource() {
   CHECK_EQ(this, instance_);
   instance_ = NULL;
 }
 
 PlatformEventSource* PlatformEventSource::GetInstance() { return instance_; }
 
@@ skipping 67 matching lines @@
 
 void PlatformEventSource::OnDispatcherListChanged() {
 }
 
 void PlatformEventSource::OnOverriddenDispatcherRestored() {
   CHECK(overridden_dispatcher_);
   overridden_dispatcher_restored_ = true;
 }
 
 }  // namespace ui