Add some trace points to mojo_shell for app lifetime

shell/application_manager/local_fetcher.cc

 // Copyright 2015 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 "shell/application_manager/local_fetcher.h"
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/format_macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/trace_event/trace_event.h"
 #include "mojo/common/common_type_converters.h"
 #include "mojo/common/data_pipe_utils.h"
 #include "url/url_util.h"
 
 namespace mojo {
 namespace shell {
 
 namespace {
 
 void IgnoreResult(bool result) {
 }
 
 }  // namespace
 
 // A loader for local files.
 LocalFetcher::LocalFetcher(const GURL& url,
                            const GURL& url_without_query,
                            const FetchCallback& loader_callback)
     : Fetcher(loader_callback), url_(url), path_(UrlToFile(url_without_query)) {
+  TRACE_EVENT0("mojo_shell", "LocalFetcher::LocalFetcher");

[viettrungluu, 2015/03/24 20:04:34]

Should you record the url (with or without query, I'm not sure)?

[jamesr, 2015/03/27 20:42:21]

Done.

   loader_callback_.Run(make_scoped_ptr(this));
 }
 
 base::FilePath LocalFetcher::UrlToFile(const GURL& url) {
   DCHECK(url.SchemeIsFile());
   url::RawCanonOutputW<1024> output;
   url::DecodeURLEscapeSequences(url.path().data(),
                                 static_cast<int>(url.path().length()), &output);
   base::string16 decoded_path = base::string16(output.data(), output.length());
 #if defined(OS_WIN)
@@ skipping 53 matching lines @@
   ReadFileToString(path_, &start_of_file, kMaxShebangLength);
   size_t return_position = start_of_file.find('\n');
   if (return_position == std::string::npos)
     return false;
   *line = start_of_file.substr(0, return_position + 1);
   return true;
 }
 
 }  // namespace shell
 }  // namespace mojo