Remove uses of base::hash_map from //chrome

chrome/browser/chromeos/input_method/input_method_util.cc

 // Copyright (c) 2012 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/input_method/input_method_util.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <functional>
@@ skipping 361 matching lines @@
 
 namespace input_method {
 
 InputMethodUtil::InputMethodUtil(InputMethodDelegate* delegate)
     : delegate_(delegate) {
   InputMethodDescriptors default_input_methods;
   default_input_methods.push_back(GetFallbackInputMethodDescriptor());
   ResetInputMethods(default_input_methods);
 
   // Initialize a map from English string to Chrome string resource ID as well.
+  // Since this array is write-once, initialize a flat map in one step with a
+  // given vector storage.
+  std::vector<EnglishToIDMap::value_type> map_storage;
+  map_storage.reserve(kEnglishToResourceIdArraySize);
   for (size_t i = 0; i < kEnglishToResourceIdArraySize; ++i) {
     const EnglishToResouceId& map_entry = kEnglishToResourceIdArray[i];
-    const bool result = english_to_resource_id_.insert(std::make_pair(
-        map_entry.english_string_from_ibus, map_entry.resource_id)).second;
-    DCHECK(result) << "Duplicated string is found: "
-                   << map_entry.english_string_from_ibus;
+    map_storage.emplace_back(map_entry.english_string_from_ibus,
+                             map_entry.resource_id);

[chrisha, 2017/05/23 20:07:59]

nit: Instead of dynamically creating a const flat_map here, can't we simply
search through the already ordered static array?

(This isn't a huge absolute cost, but duplicating memory for no reason is
wasteful. If only we also had a way to check and enforce the no-dupes and sorted
requirements at compile time...)

[brettw, 2017/06/28 23:58:39]

That would be better but I just spent 2 hours on the downloads one. I don't
think this (which I'm not even set up to test locally) would be a good use of my
time.

   }
+
+  english_to_resource_id_ =
+      EnglishToIDMap(std::move(map_storage), base::KEEP_FIRST_OF_DUPES);
+  DCHECK(english_to_resource_id_.size() == kEnglishToResourceIdArraySize)
+      << "Duplicate string is found";
 }
 
 InputMethodUtil::~InputMethodUtil() {
 }
 
 std::string InputMethodUtil::GetLocalizedDisplayName(
     const InputMethodDescriptor& descriptor) const {
   // Localizes the input method name.
   const std::string& disp = descriptor.name();
   if (base::StartsWith(disp, "__MSG_", base::CompareCase::SENSITIVE)) {
     const InputMethodNameMap* map = kInputMethodNameMap;
     size_t map_size = arraysize(kInputMethodNameMap);
     std::string name = base::ToUpperASCII(disp);
     const InputMethodNameMap map_key = {name.c_str(), 0};
     const InputMethodNameMap* p =
         std::lower_bound(map, map + map_size, map_key);
     if (p != map + map_size && name == p->message_name)
       return l10n_util::GetStringUTF8(p->resource_id);
   }
   return disp;
 }
 
 bool InputMethodUtil::TranslateStringInternal(
     const std::string& english_string, base::string16 *out_string) const {
   DCHECK(out_string);
   // |english_string| could be an input method id. So legacy xkb id is required
   // to get the translated string.
   std::string key_string = extension_ime_util::MaybeGetLegacyXkbId(
       english_string);
-  HashType::const_iterator iter = english_to_resource_id_.find(key_string);
+  auto iter = english_to_resource_id_.find(key_string);

[chrisha, 2017/05/23 20:07:59]

Just use std::binary_search?

 
   if (iter == english_to_resource_id_.end()) {
     // TODO(yusukes): Write Autotest which checks if all display names and all
     // property names for supported input methods are listed in the resource
     // ID array (crosbug.com/4572).
     LOG(ERROR) << "Resource ID is not found for: " << english_string
                << ", " << key_string;
     return false;
   }
 
@@ skipping 399 matching lines @@
       "US",
       layouts,
       languages,
       true,  // login keyboard.
       GURL(),  // options page, not available.
       GURL()); // input view page, not available.
 }
 
 }  // namespace input_method
 }  // namespace chromeos