Get the default device scale factor from monitor

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 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 "content/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 40 matching lines @@
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_view.h"
 #include "content/public/browser/web_ui_controller_factory.h"
 #include "content/public/common/bindings_policy.h"
 #include "content/public/common/content_constants.h"
 #include "content/public/common/content_restriction.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/url_constants.h"
+#include "ui/gfx/monitor.h"
+#include "ui/gfx/screen.h"
 #include "net/base/mime_util.h"
 #include "net/base/net_util.h"
 #include "net/base/network_change_notifier.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
 #include "webkit/glue/web_intent_data.h"
 #include "webkit/glue/webpreferences.h"
 
 #if defined(USE_AURA)
 #include "content/browser/web_contents/web_contents_view_aura.h"
@@ skipping 427 matching lines @@
   // chrome-devtools: pages (unless it's specifically allowed).
   if ((url.SchemeIs(chrome::kChromeDevToolsScheme) ||
       url.SchemeIs(chrome::kChromeUIScheme) ||
       (url.SchemeIs(chrome::kAboutScheme) &&
        url.spec() != chrome::kAboutBlankURL)) &&
       !command_line.HasSwitch(switches::kAllowWebUICompositing)) {
     prefs.accelerated_compositing_enabled = false;
     prefs.accelerated_2d_canvas_enabled = false;
   }
 
-  int default_device_scale_factor;
-  base::StringToInt(command_line.GetSwitchValueASCII(
-                        switches::kDefaultDeviceScaleFactor),
-                    &default_device_scale_factor);
-
-  prefs.default_device_scale_factor = default_device_scale_factor;
+  if (rvh->GetView()) {
+    gfx::Monitor monitor = gfx::Screen::GetMonitorNearestWindow(
+        rvh->GetView()->GetNativeView());
+    prefs.default_device_scale_factor =
+        static_cast<int>(monitor.device_scale_factor());
+  } else {
+    prefs.default_device_scale_factor = 1;
+  }
 
   content::GetContentClient()->browser()->OverrideWebkitPrefs(rvh, url, &prefs);
 
   return prefs;
 }
 
 NavigationControllerImpl& WebContentsImpl::GetControllerImpl() {
   return controller_;
 }
 
@@ skipping 2102 matching lines @@
 void WebContentsImpl::CreateViewAndSetSizeForRVH(RenderViewHost* rvh) {
   RenderWidgetHostView* rwh_view = GetView()->CreateViewForWidget(rvh);
   // Can be NULL during tests.
   if (rwh_view)
     rwh_view->SetSize(GetView()->GetContainerSize());
 }
 
 RenderViewHostImpl* WebContentsImpl::GetRenderViewHostImpl() {
   return static_cast<RenderViewHostImpl*>(GetRenderViewHost());
 }