[MD Settings][People] Fixes take picture button disappearing on page refresh

chrome/browser/ui/webui/settings/chromeos/change_picture_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/settings/chromeos/change_picture_handler.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 104 matching lines @@
                                 base::Unretained(this)));
 }
 
 void ChangePictureHandler::OnJavascriptAllowed() {
   registrar_.Add(this, chrome::NOTIFICATION_PROFILE_IMAGE_UPDATED,
                  content::NotificationService::AllSources());
   registrar_.Add(this, chrome::NOTIFICATION_PROFILE_IMAGE_UPDATE_FAILED,
                  content::NotificationService::AllSources());
   registrar_.Add(this, chrome::NOTIFICATION_LOGIN_USER_IMAGE_CHANGED,
                  content::NotificationService::AllSources());
+
+  camera_observer_.Add(CameraPresenceNotifier::GetInstance());
 }
 
 void ChangePictureHandler::OnJavascriptDisallowed() {
   registrar_.RemoveAll();
+
+  camera_observer_.Remove(CameraPresenceNotifier::GetInstance());
 }
 
 void ChangePictureHandler::SendDefaultImages() {
   base::ListValue image_urls;
   for (int i = default_user_image::kFirstDefaultImageIndex;
        i < default_user_image::kDefaultImagesCount; ++i) {
     std::unique_ptr<base::DictionaryValue> image_data(
         new base::DictionaryValue);
     image_data->SetString("url", default_user_image::GetDefaultImageUrl(i));
     image_data->SetString("author",
@@ skipping 58 matching lines @@
 
   ImageDecoder::Cancel(this);
   ImageDecoder::Start(this, raw_data);
 }
 
 void ChangePictureHandler::HandlePageInitialized(const base::ListValue* args) {
   DCHECK(args && args->empty());
 
   AllowJavascript();
 
-  CameraPresenceNotifier* camera = CameraPresenceNotifier::GetInstance();
-  if (!camera_observer_.IsObserving(camera))
-    camera_observer_.Add(camera);
-
   SendDefaultImages();
   SendSelectedImage();
   UpdateProfileImage();
 }
 
 void ChangePictureHandler::SendSelectedImage() {
   const user_manager::User* user = GetUser();
   DCHECK(user->GetAccountId().is_valid());
 
   previous_image_index_ = user->image_index();
@@ skipping 193 matching lines @@
   Profile* profile = Profile::FromWebUI(web_ui());
   const user_manager::User* user =
       ProfileHelper::Get()->GetUserByProfile(profile);
   if (!user)
     return user_manager::UserManager::Get()->GetActiveUser();
   return user;
 }
 
 }  // namespace settings
 }  // namespace chromeos