Add unit test for BluetoothChooserController

With more functionalities added to BluetoothChooserController,
it is necessary to add unit test to it.

BUG=639163

Review-Url: https://codereview.chromium.org/2275173002
Cr-Commit-Position: refs/heads/master@{#416408}

chrome/browser/ui/bluetooth/bluetooth_chooser_controller.cc

@@ -239,6 +239,7 @@ void BluetoothChooserController::RemoveDevice(const std::string& device_id) {
                    });
 
   if (device_it != devices_.end()) {
+    size_t index = device_it - devices_.begin();
     devices_.erase(device_it);
 
     const auto& it = device_name_counts_.find(name_it->second);
@@ -251,7 +252,7 @@ void BluetoothChooserController::RemoveDevice(const std::string& device_id) {
     device_id_to_name_map_.erase(name_it);
 
     if (view())
-      view()->OnOptionRemoved(device_it - devices_.begin());
+      view()->OnOptionRemoved(index);
   }
 }
 

chrome/chrome_tests_unit.gypi

@@ -379,6 +379,7 @@
       'browser/renderer_context_menu/render_view_context_menu_test_util.h',
       'browser/ui/autofill/country_combobox_model_unittest.cc',
       'browser/ui/autofill/save_card_bubble_controller_impl_unittest.cc',
+      'browser/ui/bluetooth/bluetooth_chooser_controller_unittest.cc',
       'browser/ui/passwords/manage_passwords_ui_controller_unittest.cc',
     ],
     'chrome_unit_tests_spellchecker_sources': [