Add WebUI::GetDeviceScale

content/public/browser/web_ui.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_BROWSER_WEB_UI_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_UI_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 34 matching lines @@
       const std::string& function_name,
       const std::vector<const base::Value*>& arg_list);
 
   virtual ~WebUI() {}
 
   virtual WebContents* GetWebContents() const = 0;
 
   virtual WebUIController* GetController() const = 0;
   virtual void SetController(WebUIController* controller) = 0;
 
+  // Returns the device scale of the monitor that the renderer is on.
+  // Whenever possible, WebUI should push resources with this scale to
+  // Javascript.
+  virtual float GetDeviceScale() const = 0;
+
   // Returns true if the favicon should be hidden for the current tab.
   virtual bool ShouldHideFavicon() const = 0;
   virtual void HideFavicon() = 0;
 
   // Returns true if the location bar should be focused by default rather than
   // the page contents. Some pages will want to use this to encourage the user
   // to type in the URL bar.
   virtual bool ShouldFocusLocationBarByDefault() const = 0;
   virtual void FocusLocationBarByDefault() = 0;
 
@@ skipping 59 matching lines @@
                                       const base::Value& arg3,
                                       const base::Value& arg4) = 0;
   virtual void CallJavascriptFunction(
       const std::string& function_name,
       const std::vector<const base::Value*>& args) = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_UI_H_