Created web::UserAgentType.

ios/chrome/browser/web/chrome_web_client.mm

 // Copyright 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.
 
 #include "ios/chrome/browser/web/chrome_web_client.h"
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/ios/ios_util.h"
 #include "base/mac/bundle_locations.h"
@@ skipping 90 matching lines @@
 base::string16 ChromeWebClient::GetPluginNotSupportedText() const {
   return l10n_util::GetStringUTF16(IDS_PLUGIN_NOT_SUPPORTED);
 }
 
 std::string ChromeWebClient::GetProduct() const {
   std::string product("CriOS/");
   product += version_info::GetVersionNumber();
   return product;
 }
 
-std::string ChromeWebClient::GetUserAgent(bool desktop_user_agent) const {
+std::string ChromeWebClient::GetUserAgent(web::UserAgentType type) const {
+  // The user agent should not be requested for app-specific URLs.
+  if (type == web::UserAgentType::NONE) {
+    NOTREACHED();
+    return std::string();

[Eugene But (OOO till 7-30), 2017/02/25 01:51:52]

DCHECK_NE(type, web::UserAgentType::NONE);

See Chromium Style Guide:
https://chromium.googlesource.com/chromium/src/+/master/styleguide/c++/c++.md...

[kkhorimoto, 2017/02/27 23:29:04]

Hmm, I had not seen those guidelines before.  I guess since there isn't any harm
in returning an inaccurate UA string here, I'll just use the DCHECK.

+  }
+
   // Using desktop user agent overrides a command-line user agent, so that
   // request desktop site can still work when using an overridden UA.
-  if (desktop_user_agent) {
+  if (type == web::UserAgentType::DESKTOP)
     return base::SysNSStringToUTF8(ChromeWebView::kDesktopUserAgent);
-  }
 
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kUserAgent)) {
     std::string user_agent =
         command_line->GetSwitchValueASCII(switches::kUserAgent);
     if (net::HttpUtil::IsValidHeaderValue(user_agent))
       return user_agent;
     LOG(WARNING) << "Ignored invalid value for flag --" << switches::kUserAgent;
   }
 
   std::string product = GetProduct();
   return web::BuildUserAgentFromProduct(product);

[Eugene But (OOO till 7-30), 2017/02/25 01:51:52]

Optional nit: Since you touching this.
return web::BuildUserAgentFromProduct(GetProduct());

[kkhorimoto, 2017/02/27 23:29:04]

Done.

 }
 
 base::string16 ChromeWebClient::GetLocalizedString(int message_id) const {
   return l10n_util::GetStringUTF16(message_id);
 }
 
 base::StringPiece ChromeWebClient::GetDataResource(
     int resource_id,
     ui::ScaleFactor scale_factor) const {
   return ResourceBundle::GetSharedInstance().GetRawDataResourceForScale(
@@ skipping 39 matching lines @@
   // If this call fails, web will fall back to the default params.
   *params_vector =
       task_scheduler_util::GetBrowserWorkerPoolParamsFromVariations();
   *index_to_traits_callback =
       base::Bind(&task_scheduler_util::BrowserWorkerPoolIndexForTraits);
 }
 
 void ChromeWebClient::PerformExperimentalTaskSchedulerRedirections() {
   task_scheduler_util::MaybePerformBrowserTaskSchedulerRedirection();
 }