Tracks changes to zoom icon and zoom percentage. Notifies browser window if the icon should be chan…

chrome/browser/ui/zoom/zoom_tab_helper.cc

+// Copyright (c) 2012 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_tab_helper.h"
+
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/pref_names.h"
+#include "content/public/browser/notification_types.h"
+#include "content/public/browser/notification_details.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/common/page_zoom.h"
+
+ZoomTabHelper::ZoomTabHelper(TabContentsWrapper* tab_contents)
+    : content::WebContentsObserver(tab_contents->web_contents()),
+      tab_contents_wrapper_(tab_contents),
+      delegate_(NULL) {
+  default_zoom_level_.Init(prefs::kDefaultZoomLevel,
+                           tab_contents->profile()->GetPrefs(), this);
+  registrar_.Add(this, content::NOTIFICATION_ZOOM_LEVEL_CHANGED,
+                 content::NotificationService::AllBrowserContextsAndSources());
+
+  UpdateState();
+}
+
+ZoomTabHelper::~ZoomTabHelper() {
+  default_zoom_level_.Destroy();
+  registrar_.RemoveAll();
+}
+
+void ZoomTabHelper::DidNavigateMainFrame(
+    const content::LoadCommittedDetails& details,
+    const content::FrameNavigateParams& params) {
+  // If the main frame's content has changed, the new page may have a different
+  // zoom level from the old one.
+  UpdateState();
+}
+
+void ZoomTabHelper::Observe(int type,
+                            const content::NotificationSource& source,
+                            const content::NotificationDetails& details) {
+  switch (type) {
+    case chrome::NOTIFICATION_PREF_CHANGED: {
+      std::string* pref_name = content::Details<std::string>(details).ptr();
+      DCHECK(pref_name && *pref_name == prefs::kDefaultZoomLevel);
+    }
+      // Fall through.
+    case content::NOTIFICATION_ZOOM_LEVEL_CHANGED:
+      UpdateState();
+      break;
+    default:
+      NOTREACHED();
+  }
+}
+
+void ZoomTabHelper::UpdateState() {
+  double currentZoomLevel =
+      tab_contents_wrapper_->web_contents()->GetZoomLevel();
+  double defaultZoomLevel = default_zoom_level_.GetValue();
+
+  ZoomIconState state;
+  if (content::ZoomValuesEqual(currentZoomLevel, defaultZoomLevel))
+    state = NONE;
+  else if (currentZoomLevel > defaultZoomLevel)
+    state = ZOOM_PLUS_ICON;
+  else
+    state = ZOOM_MINUS_ICON;
+
+  bool dummy;
+  int zoomPercent = tab_contents_wrapper_->web_contents()->
+      GetZoomPercent(&dummy, &dummy);
+
+  if (state != zoom_icon_state_) {
+    zoom_icon_state_ = state;
+    if (delegate())
+      delegate()->ZoomIconStateChanged(tab_contents_wrapper_,
+                                       state,
+                                       zoomPercent);
+  }
+
+  if (zoomPercent != zoom_percent_) {
+    zoom_percent_ = zoomPercent;
+    if (delegate())
+      delegate()->ZoomChanged(tab_contents_wrapper_, zoomPercent);
+  }
+}