Split run_tool.py into run_tool.py, extract_edits.py and apply_edits.py

tools/clang/translation_unit/TranslationUnitGenerator.cpp

 // 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.
 //
 // This implements a Clang tool to generate compilation information that is
 // sufficient to recompile the code with clang. For each compilation unit, all
 // source files which are necessary for compiling it are determined. For each
 // compilation unit, a file is created containing a list of all file paths of
 // included files.
 
@@ skipping 247 matching lines @@
 
 static llvm::cl::extrahelp common_help(CommonOptionsParser::HelpMessage);
 
 int main(int argc, const char* argv[]) {
   llvm::cl::OptionCategory category("TranslationUnitGenerator Tool");
   CommonOptionsParser options(argc, argv, category);
   std::unique_ptr<clang::tooling::FrontendActionFactory> frontend_factory =
       clang::tooling::newFrontendActionFactory<CompilationIndexerAction>();
   clang::tooling::ClangTool tool(options.getCompilations(),
                                  options.getSourcePathList());
-  // This clang tool does not actually produce edits, but run_tool.py expects
-  // this. So we just print an empty edit block.
-  llvm::outs() << "==== BEGIN EDITS ====\n";
-  llvm::outs() << "==== END EDITS ====\n";
   return tool.run(frontend_factory.get());
 }