[Cronet] Add CrNet.setUserAgent method on iOS.

ios/crnet/crnet_environment.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/crnet/crnet_environment.h"
 
 #import <Foundation/Foundation.h>
 
 #include <utility>
 
@@ skipping 246 matching lines @@
       GetHttpNetworkSession(GetMainContextGetter()->GetURLRequestContext());
 
   if (http_network_session) {
     net::SpdySessionPool *spdy_session_pool =
         http_network_session->spdy_session_pool();
     if (spdy_session_pool)
       spdy_session_pool->CloseCurrentSessions(net::ERR_ABORTED);
   }
 }
 
-CrNetEnvironment::CrNetEnvironment(const std::string& user_agent_product_name)
+CrNetEnvironment::CrNetEnvironment(const std::string& user_agent,
+                                   bool user_agent_partial)
     : spdy_enabled_(false),
       quic_enabled_(false),
       sdch_enabled_(false),
       main_context_(new net::URLRequestContext),
-      user_agent_product_name_(user_agent_product_name),
+      user_agent_(user_agent),
+      user_agent_partial_(user_agent_partial),
       net_log_(new net::NetLog) {}
 
 void CrNetEnvironment::Install() {
   // Threads setup.
   network_cache_thread_.reset(new base::Thread("Chrome Network Cache Thread"));
   network_cache_thread_->StartWithOptions(
       base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
   network_io_thread_.reset(new base::Thread("Chrome Network IO Thread"));
   network_io_thread_->StartWithOptions(
       base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
@@ skipping 92 matching lines @@
       @"Localizable",
       bundle,
       @"en-US,en",
       @"These values are copied from Chrome's .xtb files, so the same "
        "values are used in the |Accept-Language| header. Key name matches "
        "Chrome's.");
   if (acceptableLanguages == Nil)
     acceptableLanguages = @"en-US,en";
   std::string acceptable_languages =
       [acceptableLanguages cStringUsingEncoding:NSUTF8StringEncoding];
-  std::string user_agent =
-      web::BuildUserAgentFromProduct(user_agent_product_name_);
+  if (user_agent_partial_) {
+    user_agent_ = web::BuildUserAgentFromProduct(user_agent_);
+    user_agent_partial_ = false;
+  }
   // Set the user agent through NSUserDefaults. This sets it for both
   // UIWebViews and WKWebViews, and javascript calls to navigator.userAgent
   // return this value.
   [[NSUserDefaults standardUserDefaults] registerDefaults:@{
-    @"UserAgent" : [NSString stringWithUTF8String:user_agent.c_str()]
+    @"UserAgent" : [NSString stringWithUTF8String:user_agent_.c_str()]
   }];
   main_context_->set_http_user_agent_settings(
-      new net::StaticHttpUserAgentSettings(acceptable_languages, user_agent));
+      new net::StaticHttpUserAgentSettings(acceptable_languages, user_agent_));
 
   main_context_->set_ssl_config_service(new net::SSLConfigServiceDefaults);
   main_context_->set_transport_security_state(
       new net::TransportSecurityState());
   main_context_->set_cert_transparency_verifier(new net::MultiLogCTVerifier());
   main_context_->set_ct_policy_enforcer(new net::CTPolicyEnforcer());
   http_server_properties_.reset(new net::HttpServerPropertiesImpl());
   main_context_->set_http_server_properties(http_server_properties_.get());
   // TODO(rdsmith): Note that the ".release()" calls below are leaking
   // the objects in question; this should be fixed by having an object
@@ skipping 88 matching lines @@
 
   return user_agent_settings->GetUserAgent();
 }
 
 void CrNetEnvironment::ClearCache(ClearCacheCallback callback) {
   PostToNetworkThread(
       FROM_HERE,
       base::Bind(&net::ClearHttpCache, main_context_getter_,
                  network_io_thread_->task_runner(), base::BindBlock(callback)));
 }