base: Remove the string logging from CHECK().

tools/gn/ninja_copy_target_writer.cc

 // Copyright (c) 2013 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 "tools/gn/ninja_copy_target_writer.h"
 
 #include "base/strings/string_util.h"
 #include "tools/gn/ninja_utils.h"
 #include "tools/gn/output_file.h"
 #include "tools/gn/scheduler.h"
@@ skipping 45 matching lines @@
   WriteCopyRules(&output_files);
   out_ << std::endl;
   WriteStampForTarget(output_files, std::vector<OutputFile>());
 }
 
 void NinjaCopyTargetWriter::WriteCopyRules(
     std::vector<OutputFile>* output_files) {
   CHECK(target_->action_values().outputs().list().size() == 1);
   const SubstitutionList& output_subst_list =
       target_->action_values().outputs();
-  CHECK_EQ(1u, output_subst_list.list().size())
-      << "Should have one entry exactly.";
+  // Should have one entry exactly.
+  CHECK_EQ(1u, output_subst_list.list().size());
   const SubstitutionPattern& output_subst = output_subst_list.list()[0];
 
   std::string tool_name =
       GetNinjaRulePrefixForToolchain(settings_) +
       Toolchain::ToolTypeToName(Toolchain::TYPE_COPY);
 
   OutputFile input_dep =
       WriteInputDepsStampAndGetDep(std::vector<const Target*>());
 
   // Note that we don't write implicit deps for copy steps. "copy" only
@@ skipping 32 matching lines @@
     path_output_.WriteFile(out_, output_file);
     out_ << ": " << tool_name << " ";
     path_output_.WriteFile(out_, input_file);
     if (!input_dep.value().empty()) {
       out_ << " || ";
       path_output_.WriteFile(out_, input_dep);
     }
     out_ << std::endl;
   }
 }