Use devtools to set user agent in chromedriver

chrome/test/chromedriver/chrome/mobile_emulation_override_manager.cc

 // 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 "chrome/test/chromedriver/chrome/mobile_emulation_override_manager.h"
 
 #include "base/values.h"
 #include "chrome/test/chromedriver/chrome/device_metrics.h"
 #include "chrome/test/chromedriver/chrome/devtools_client.h"
 #include "chrome/test/chromedriver/chrome/status.h"
 
 MobileEmulationOverrideManager::MobileEmulationOverrideManager(
     DevToolsClient* client,
-    const DeviceMetrics* device_metrics)
+    const DeviceMetrics* device_metrics,
+    std::string user_agent)
     : client_(client),
-      overridden_device_metrics_(device_metrics) {
-  if (overridden_device_metrics_)
+      overridden_device_metrics_(device_metrics),
+      overridden_user_agent_(user_agent) {
+  if (overridden_device_metrics_ || !overridden_user_agent_.empty())
     client_->AddListener(this);
 }
 
 MobileEmulationOverrideManager::~MobileEmulationOverrideManager() {
 }
 
 Status MobileEmulationOverrideManager::OnConnected(DevToolsClient* client) {
   return ApplyOverrideIfNeeded();
 }
 
 Status MobileEmulationOverrideManager::OnEvent(
     DevToolsClient* client,
     const std::string& method,
     const base::DictionaryValue& params) {
   if (method == "Page.frameNavigated") {
     const base::Value* unused_value;
     if (!params.Get("frame.parentId", &unused_value))
       return ApplyOverrideIfNeeded();
   }
   return Status(kOk);
 }
 
 bool MobileEmulationOverrideManager::IsEmulatingTouch() {
   return overridden_device_metrics_ && overridden_device_metrics_->touch;
 }
 
 Status MobileEmulationOverrideManager::ApplyOverrideIfNeeded() {
+  if (!overridden_user_agent_.empty()) {
+    base::DictionaryValue net_enable_params, user_agent_params;
+    net_enable_params.SetInteger("maxTotalBufferSize", 0);
+    net_enable_params.SetInteger("maxResourceBufferSize", 0);
+    Status status = client_->SendCommand("Network.enable", net_enable_params);
+
+    user_agent_params.SetString("userAgent", overridden_user_agent_);
+    status =
+        client_->SendCommand("Network.setUserAgentOverride", user_agent_params);
+    if (status.IsError())
+      return status;
+  }
+
   if (overridden_device_metrics_ == NULL)
     return Status(kOk);
 
   base::DictionaryValue params;
   params.SetInteger("width", overridden_device_metrics_->width);
   params.SetInteger("height", overridden_device_metrics_->height);
   params.SetDouble("deviceScaleFactor",
                    overridden_device_metrics_->device_scale_factor);
   params.SetBoolean("mobile", overridden_device_metrics_->mobile);
   params.SetBoolean("fitWindow", overridden_device_metrics_->fit_window);
   params.SetBoolean("textAutosizing",
                     overridden_device_metrics_->text_autosizing);
   params.SetDouble("fontScaleFactor",
                    overridden_device_metrics_->font_scale_factor);
   Status status = client_->SendCommand("Page.setDeviceMetricsOverride", params);
   if (status.IsError())
     return status;
 
   if (overridden_device_metrics_->touch) {
     base::DictionaryValue emulate_touch_params;
     emulate_touch_params.SetBoolean("enabled", true);
     status = client_->SendCommand("Emulation.setTouchEmulationEnabled",
                                   emulate_touch_params);
   }
 
   return Status(kOk);
 }