Add default zoom functionality to chrome.tabs Zoom API.

chrome/browser/extensions/api/tabs/tabs_api.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/extensions/api/tabs/tabs_api.h"
 
 #include <algorithm>
 #include <limits>
 #include <vector>
 
@@ skipping 1836 matching lines @@
   WebContents* web_contents = GetWebContents(tab_id);
   if (!web_contents)
     return false;
 
   GURL url(web_contents->GetVisibleURL());
   if (PermissionsData::IsRestrictedUrl(url, url, extension(), &error_))
     return false;
 
   ZoomController* zoom_controller =
       ZoomController::FromWebContents(web_contents);
-  double zoom_level = content::ZoomFactorToZoomLevel(params->zoom_factor);
+  double zoom_level = params->zoom_factor > 0
+                          ? content::ZoomFactorToZoomLevel(params->zoom_factor)
+                          : zoom_controller->GetDefaultZoomLevel();
 
   scoped_refptr<ExtensionZoomRequestClient> client(
       new ExtensionZoomRequestClient(extension()));
   if (!zoom_controller->SetZoomLevelByClient(zoom_level, client)) {
     // Tried to zoom a tab in disabled mode.
     error_ = keys::kCannotZoomDisabledTabError;
     return false;
   }
 
   SendResponse(true);
@@ skipping 78 matching lines @@
   int tab_id = params->tab_id ? *params->tab_id : -1;
   WebContents* web_contents = GetWebContents(tab_id);
   if (!web_contents)
     return false;
   ZoomController* zoom_controller =
       ZoomController::FromWebContents(web_contents);
 
   ZoomController::ZoomMode zoom_mode = zoom_controller->zoom_mode();
   api::tabs::ZoomSettings zoom_settings;
   ZoomModeToZoomSettings(zoom_mode, &zoom_settings);
+  zoom_settings.default_zoom_factor.reset(new double(
+      content::ZoomLevelToZoomFactor(zoom_controller->GetDefaultZoomLevel())));
 
   results_ = api::tabs::GetZoomSettings::Results::Create(zoom_settings);
   SendResponse(true);
   return true;
 }
 
 }  // namespace extensions