Zoom Extension API (chrome)

chrome/browser/ui/zoom/zoom_event_manager.cc

+// Copyright 2014 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/zoom/zoom_event_manager.h"
+
+#include "content/public/browser/browser_context.h"
+
+namespace {
+static const char kBrowserZoomEventManager[] = "browser_zoom_event_manager";
+}
+
+ZoomEventManager* ZoomEventManager::GetForBrowserContext(
+    content::BrowserContext* context) {
+  if (!context->GetUserData(kBrowserZoomEventManager))
+    context->SetUserData(kBrowserZoomEventManager, new ZoomEventManager);
+  return static_cast<ZoomEventManager*>(
+      context->GetUserData(kBrowserZoomEventManager));
+}
+
+ZoomEventManager::ZoomEventManager() {}
+
+ZoomEventManager::~ZoomEventManager() {}
+
+void ZoomEventManager::OnZoomLevelChanged(
+    const content::HostZoomMap::ZoomLevelChange& change) {
+  zoom_level_changed_callbacks_.Notify(change);
+}
+
+scoped_ptr<content::HostZoomMap::Subscription>
+ZoomEventManager::AddZoomLevelChangedCallback(
+    const content::HostZoomMap::ZoomLevelChangedCallback& callback) {
+  return zoom_level_changed_callbacks_.Add(callback);
+}