[Chromecast] Handle device scale factor correctly

chromecast/browser/service/cast_service_simple.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 "chromecast/browser/service/cast_service_simple.h"
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "chromecast/browser/cast_content_window.h"
 #include "content/public/browser/render_view_host.h"
@@ skipping 33 matching lines @@
 }
 
 void CastServiceSimple::InitializeInternal() {
   startup_url_ = GetStartupURL();
 }
 
 void CastServiceSimple::FinalizeInternal() {
 }
 
 void CastServiceSimple::StartInternal() {
-  // This is the simple version that hard-codes the size.
-  gfx::Size initial_size(1280, 720);
-
   window_.reset(new CastContentWindow);
-  web_contents_ = window_->CreateWebContents(initial_size, browser_context());
-  window_->CreateWindowTree(initial_size, web_contents_.get());
+  web_contents_ = window_->CreateWebContents(browser_context());
+  window_->CreateWindowTree(web_contents_.get());
 
   web_contents_->GetController().LoadURL(startup_url_, content::Referrer(),
                                          ui::PAGE_TRANSITION_TYPED,
                                          std::string());
 }
 
 void CastServiceSimple::StopInternal() {
   web_contents_->ClosePage();
   web_contents_.reset();
   window_.reset();
 }
 
 }  // namespace shell
 }  // namespace chromecast