Created web::UserAgentType.

ios/chrome/browser/web/chrome_web_client.mm

Index: ios/chrome/browser/web/chrome_web_client.mm
diff --git a/ios/chrome/browser/web/chrome_web_client.mm b/ios/chrome/browser/web/chrome_web_client.mm
index ccf042f332e166d5afd3775ff80fd8170d17cb16..f51bfe882deec7afe9b8ab565c60d4bb2dd1cbe1 100644
--- a/ios/chrome/browser/web/chrome_web_client.mm
+++ b/ios/chrome/browser/web/chrome_web_client.mm
@@ -108,12 +108,17 @@
   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();

[liaoyuke, 2017/02/25 01:28:19]

Do we really need this return statement?

[kkhorimoto, 2017/02/25 01:35:05]

Yes, NOTREACHED() does nothing in non-debug builds, so we still need a return
statement in order for it to compile.

[liaoyuke, 2017/02/25 01:40:55]

I think it will compile even without this return, because this function always
returns something at the end. Could you please double-check?

[kkhorimoto, 2017/02/25 01:52:09]

It will compile, but it will return the wrong value.  If we allowed it to keep
going without an early return, the function will return the UA for
UserAgentType::MOBILE, which is not what was requested for the input parameter.

+  }
+
   // 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)) {