base: Remove the string logging from CHECK().

chrome/browser/chromeos/login/mixin_based_browser_test.cc

 // Copyright (c) 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 "chrome/browser/chromeos/login/mixin_based_browser_test.h"
 
 namespace chromeos {
 
 MixinBasedBrowserTest::MixinBasedBrowserTest() : setup_was_launched_(false) {
 }
@@ skipping 39 matching lines @@
 void MixinBasedBrowserTest::TearDownInProcessBrowserTestFixture() {
   InProcessBrowserTest::TearDownInProcessBrowserTestFixture();
   for (ScopedVector<Mixin>::reverse_iterator it = mixins_.rbegin();
        it != mixins_.rend();
        ++it) {
     (*it)->TearDownInProcessBrowserTestFixture();
   }
 }
 
 void MixinBasedBrowserTest::AddMixin(MixinBasedBrowserTest::Mixin* mixin) {
-  CHECK(!setup_was_launched_)
-      << "You are trying to add a mixin after setting up has already started.";
+  // You are trying to add a mixin after setting up has already started.
+  CHECK(!setup_was_launched_);
   mixins_.push_back(mixin);
 }
 
 }  // namespace chromeos