Disable surprise me automatically if the current wallpaper was set by a third party application.

chrome/browser/chromeos/extensions/wallpaper_api.cc

 // Copyright 2013 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/chromeos/extensions/wallpaper_api.h"
 
 #include <string>
 #include <vector>
 
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "base/files/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/worker_pool.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/chromeos/extensions/wallpaper_private_api.h"
 #include "chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/pref_names.h"
 #include "components/user_manager/user.h"
 #include "components/user_manager/user_manager.h"
 #include "components/wallpaper/wallpaper_layout.h"
+#include "extensions/browser/event_router.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "url/gurl.h"
 
 using base::BinaryValue;
 using content::BrowserThread;
 
 typedef base::Callback<void(bool success, const std::string&)> FetchCallback;
@@ skipping 133 matching lines @@
     Profile* profile = Profile::FromBrowserContext(browser_context());
     if (extension()->id() == extension_misc::kWallpaperManagerId) {
       profile->GetPrefs()->SetString(prefs::kCurrentWallpaperAppName,
                                      std::string());
     } else {
       profile->GetPrefs()->SetString(prefs::kCurrentWallpaperAppName,
                                      extension()->name());
     }
     SendResponse(true);
   }
+
+  // Inform the native Wallpaper Picker Application that the current wallpaper
+  // has been modified by a third party application.
+  Profile* profile = Profile::FromBrowserContext(browser_context());
+  extensions::EventRouter* event_router = extensions::EventRouter::Get(profile);
+  scoped_ptr<base::ListValue> event_args(new base::ListValue());
+  scoped_ptr<extensions::Event> event(
+      new extensions::Event(extensions::api::wallpaper_private::
+                                OnWallpaperChangedBy3rdParty::kEventName,
+                            event_args.Pass()));
+  event_router->DispatchEventToExtension(extension_misc::kWallpaperManagerId,
+                                         event.Pass());
 }
 
 void WallpaperSetWallpaperFunction::GenerateThumbnail(
     const base::FilePath& thumbnail_path, scoped_ptr<gfx::ImageSkia> image) {
   DCHECK(BrowserThread::GetBlockingPool()->IsRunningSequenceOnCurrentThread(
       sequence_token_));
   if (!base::PathExists(thumbnail_path.DirName()))
     base::CreateDirectory(thumbnail_path.DirName());
 
   scoped_refptr<base::RefCountedBytes> data;
@@ skipping 21 matching lines @@
     const std::string& response) {
   if (success) {
     params_->details.data.reset(
         new std::vector<char>(response.begin(), response.end()));
     StartDecode(*params_->details.data);
   } else {
     SetError(response);
     SendResponse(false);
   }
 }