Add signal strength indicator icon to WebBluetooth chooser on non-Mac desktops

chrome/browser/usb/usb_chooser_controller.h

 // Copyright 2015 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 CHROME_BROWSER_USB_USB_CHOOSER_CONTROLLER_H_
 #define CHROME_BROWSER_USB_USB_CHOOSER_CONTROLLER_H_
 
 #include <unordered_map>
 #include <utility>
 #include <vector>
@@ skipping 22 matching lines @@
                              public device::UsbService::Observer {
  public:
   UsbChooserController(
       content::RenderFrameHost* owner,
       mojo::Array<device::usb::DeviceFilterPtr> device_filters,
       content::RenderFrameHost* render_frame_host,
       const device::usb::ChooserService::GetPermissionCallback& callback);
   ~UsbChooserController() override;
 
   // ChooserController:
+  bool HasIconBeforeText() const override;
   base::string16 GetNoOptionsText() const override;
   base::string16 GetOkButtonLabel() const override;
   size_t NumOptions() const override;
+  int GetSignalStrengthLevel(size_t index) const override;

[Reilly Grant (use Gerrit), 2016/08/12 20:28:16]

ChooserController could be given a default implementation of these methods to
avoid code churn for chooser types that don't need them.

[juncai, 2016/08/15 21:53:20]

Done.

   base::string16 GetOption(size_t index) const override;
   void RefreshOptions() override;
   base::string16 GetStatus() const override;
   void Select(size_t index) override;
   void Cancel() override;
   void Close() override;
   void OpenHelpCenterUrl() const override;
 
   // device::UsbService::Observer:
   void OnDeviceAdded(scoped_refptr<device::UsbDevice> device) override;
@@ skipping 13 matching lines @@
   std::vector<std::pair<scoped_refptr<device::UsbDevice>, base::string16>>
       devices_;
   // Maps from device name to number of devices.
   std::unordered_map<base::string16, int> device_name_map_;
   base::WeakPtrFactory<UsbChooserController> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(UsbChooserController);
 };
 
 #endif  // CHROME_BROWSER_USB_USB_CHOOSER_CONTROLLER_H_