Replace uses of hash_map in //base

base/trace_event/trace_log.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 "base/trace_event/trace_log.h"
 
 #include <algorithm>
 #include <cmath>
 #include <memory>
 #include <utility>
@@ skipping 1211 matching lines @@
     // Check if the thread name has been set or changed since the previous
     // call (if any), but don't bother if the new name is empty. Note this will
     // not detect a thread name change within the same char* buffer address: we
     // favor common case performance over corner case correctness.
     static auto* current_thread_name = new ThreadLocalPointer<const char>();
     if (new_name != current_thread_name->Get() && new_name && *new_name) {
       current_thread_name->Set(new_name);
 
       AutoLock thread_info_lock(thread_info_lock_);
 
-      hash_map<int, std::string>::iterator existing_name =
-          thread_names_.find(thread_id);
+      auto existing_name = thread_names_.find(thread_id);
       if (existing_name == thread_names_.end()) {
         // This is a new thread id, and a new name.
         thread_names_[thread_id] = new_name;
       } else {
         // This is a thread id that we've seen before, but potentially with a
         // new name.
         std::vector<StringPiece> existing_names = base::SplitStringPiece(
             existing_name->second, ",", base::KEEP_WHITESPACE,
             base::SPLIT_WANT_NONEMPTY);
         bool found = std::find(existing_names.begin(), existing_names.end(),
@@ skipping 491 matching lines @@
 }
 
 ScopedTraceBinaryEfficient::~ScopedTraceBinaryEfficient() {
   if (*category_group_enabled_) {
     TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(category_group_enabled_, name_,
                                                 event_handle_);
   }
 }
 
 }  // namespace trace_event_internal