Site Settings Desktop: Implement Zoom Levels category.

BUG=635846, 614277
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2323693002
Cr-Commit-Position: refs/heads/master@{#417554}

chrome/app/settings_strings.grdp

@@ -1563,6 +1563,9 @@
   <message name="IDS_SETTINGS_SITE_SETTINGS_FULLSCREEN" desc="Label for the fullscreen site settings.">
     Fullscreen
   </message>
+  <message name="IDS_SETTINGS_SITE_SETTINGS_ZOOM_LEVELS" desc="Label for the Zoom levels category in site settings.">
+    Zoom levels
+  </message>
   <message name="IDS_SETTINGS_SITE_SETTINGS_MAY_SAVE_COOKIES" desc="Label for the cookies option description site settings.">
     Sites can save and read cookie data
   </message>
@@ -1761,6 +1764,9 @@
   <message name="IDS_SETTINGS_SITE_SETTINGS_INCOGNITO_EMBEDDED" desc="A label for a site rule that specifies an embedded origin and only applies to the current incognito session.">
     Current incognito session (<ph name="EMBEDDING">$1<ex>embedded on google.com</ex></ph>)
   </message>
+  <message name="IDS_SETTINGS_SITE_SETTINGS_NO_ZOOMED_SITES" desc="A label explaining that no sites have a configured zoom in/out value.">
+    No sites have been zoomed in or out.
+  </message>
 
   <!-- Sync / People Page -->
   <message name="IDS_SETTINGS_PEOPLE" desc="Name of the settings page which manages Chrome's signed-in Google profile.">

chrome/browser/resources/settings/privacy_page/privacy_page.html

@@ -16,6 +16,7 @@
 <link rel="import" href="/site_settings/protocol_handlers.html">
 <link rel="import" href="/site_settings/usb_devices.html">
 <link rel="import" href="/site_settings/site_data.html">
+<link rel="import" href="/site_settings/zoom_levels.html">
 <link rel="import" href="/site_settings_page/site_settings_page.html">
 
 <if expr="use_nss_certs">
@@ -230,6 +231,11 @@
           <protocol-handlers></protocol-handlers>
         </settings-subpage>
       </template>
+      <template is="dom-if" route-path="/siteSettings/zoomLevels" no-search>
+        <settings-subpage page-title="$i18n{siteSettingsCategoryZoomLevels}">
+          <zoom-levels></zoom-levels>
+        </settings-subpage>
+      </template>
       <template is="dom-if" route-path="/siteSettings/javascript" no-search>
         <settings-subpage page-title="$i18n{siteSettingsCategoryJavascript}">
           <site-settings-category

chrome/browser/resources/settings/route.js

@@ -158,6 +158,7 @@ cr.define('settings', function() {
   r.SITE_SETTINGS_UNSANDBOXED_PLUGINS =
       r.SITE_SETTINGS.createChild('unsandboxedPlugins');
   r.SITE_SETTINGS_USB_DEVICES = r.SITE_SETTINGS.createChild('usbDevices');
+  r.SITE_SETTINGS_ZOOM_LEVELS = r.SITE_SETTINGS.createChild('zoomLevels');
 
 <if expr="chromeos">
   r.DATETIME = r.ADVANCED.createSection('/dateTime', 'dateTime');

chrome/browser/resources/settings/settings_resources.grd

@@ -907,6 +907,12 @@
       <structure name="IDR_SETTINGS_WEBSITE_USAGE_PRIVATE_API_JS"
                  file="site_settings/website_usage_private_api.js"
                  type="chrome_html" />
+      <structure name="IDR_SETTINGS_ZOOM_LEVELS_HTML"
+                 file="site_settings/zoom_levels.html"
+                 type="chrome_html" />
+      <structure name="IDR_SETTINGS_ZOOM_LEVELS_JS"
+                 file="site_settings/zoom_levels.js"
+                 type="chrome_html" />
       <if expr="chromeos">
         <structure name="IDR_SETTINGS_BLUETOOTH_DEVICE_DIALOG_HTML"
                    file="bluetooth_page/bluetooth_device_dialog.html"

chrome/browser/resources/settings/site_settings/compiled_resources2.gyp

@@ -170,5 +170,13 @@
       ],
       'includes': ['../../../../../third_party/closure_compiler/compile_js2.gypi'],
     },
+    {
+      'target_name': 'zoom_levels',
+      'dependencies': [
+        '<(DEPTH)/ui/webui/resources/js/compiled_resources2.gyp:web_ui_listener_behavior',
+        'site_settings_behavior',
+      ],
+      'includes': ['../../../../../third_party/closure_compiler/compile_js2.gypi'],
+    },
   ],
 }

chrome/browser/resources/settings/site_settings/constants.js

@@ -28,6 +28,7 @@ cr.define('settings', function() {
     KEYGEN: 'keygen',
     BACKGROUND_SYNC: 'background-sync',
     USB_DEVICES: 'usb-chooser-data',
+    ZOOM_LEVELS: 'zoom-levels',
   };
 
   /**

chrome/browser/resources/settings/site_settings/site_list.js

@@ -281,9 +281,10 @@ Polymer({
       if (settings.ContentSettingsTypes[type] ==
           settings.ContentSettingsTypes.PROTOCOL_HANDLERS ||
           settings.ContentSettingsTypes[type] ==
-          settings.ContentSettingsTypes.USB_DEVICES) {
-        // Protocol handlers and USB devices don't have data stored the way all
-        // the other categories do.
+          settings.ContentSettingsTypes.USB_DEVICES ||
+          settings.ContentSettingsTypes[type] ==
+          settings.ContentSettingsTypes.ZOOM_LEVELS) {
+        // Some categories store their data in a custom way.
         continue;
       }
 

chrome/browser/resources/settings/site_settings/site_settings_behavior.js

@@ -71,6 +71,8 @@ var SiteSettingsBehaviorImpl = {
         return 'unsandboxed-plugins';
       case settings.ContentSettingsTypes.USB_DEVICES:
         return 'usb-devices';
+      case settings.ContentSettingsTypes.ZOOM_LEVELS:
+        return 'zoom-levels';
       default:
         return '';
     }
@@ -114,6 +116,8 @@ var SiteSettingsBehaviorImpl = {
         return settings.Route.SITE_SETTINGS_UNSANDBOXED_PLUGINS;
       case settings.ContentSettingsTypes.USB_DEVICES:
         return settings.Route.SITE_SETTINGS_USB_DEVICES;
+      case settings.ContentSettingsTypes.ZOOM_LEVELS:
+        return settings.Route.SITE_SETTINGS_ZOOM_LEVELS;
     }
     assertNotReached();
   },
@@ -160,6 +164,8 @@ var SiteSettingsBehaviorImpl = {
         return 'cr:extension';
       case settings.ContentSettingsTypes.USB_DEVICES:
         return 'settings:usb';
+      case settings.ContentSettingsTypes.ZOOM_LEVELS:
+        return 'settings:zoom-in';
       default:
         assertNotReached('Invalid category: ' + category);
         return '';
@@ -208,6 +214,8 @@ var SiteSettingsBehaviorImpl = {
         return loadTimeData.getString('siteSettingsUnsandboxedPlugins');
       case settings.ContentSettingsTypes.USB_DEVICES:
         return loadTimeData.getString('siteSettingsUsbDevices');
+      case settings.ContentSettingsTypes.ZOOM_LEVELS:
+        return loadTimeData.getString('siteSettingsZoomLevels');
       default:
         assertNotReached('Invalid category: ' + category);
         return '';
@@ -327,7 +335,7 @@ var SiteSettingsBehaviorImpl = {
                 'siteSettingsUnsandboxedPluginsAskRecommended') :
             loadTimeData.getString('siteSettingsUnsandboxedPluginsAsk');
       default:
-        assertNotReached();
+        assertNotReached('Invalid category: ' + category);
         return '';
     }
   },

chrome/browser/resources/settings/site_settings/site_settings_prefs_browser_proxy.js

@@ -66,6 +66,14 @@ var UsbDeviceDetails;
  */
 var UsbDeviceEntry;
 
+/**
+ * @typedef {{origin: string,
+ *            setting: string,
+ *            source: string,
+ *            zoom: string}}
+ */
+var ZoomLevelEntry;
+
 cr.define('settings', function() {
   /** @interface */
   function SiteSettingsPrefsBrowserProxy() {}
@@ -216,6 +224,18 @@ cr.define('settings', function() {
      * profile exists). Returns the results via onIncognitoStatusChanged.
      */
     updateIncognitoStatus: function() {},
+
+    /**
+     * Fetches the currently defined zoom levels for sites. Returns the results
+     * via onZoomLevelsChanged.
+     */
+    fetchZoomLevels: function() {},
+
+    /**
+     * Removes a zoom levels for a given host.
+     * @param {string} host The host to remove zoom levels for.
+     */
+    removeZoomLevel: function(host) {},
   };
 
   /**
@@ -326,6 +346,16 @@ cr.define('settings', function() {
     updateIncognitoStatus: function() {
       chrome.send('updateIncognitoStatus');
     },
+
+    /** @override */
+    fetchZoomLevels: function() {
+      chrome.send('fetchZoomLevels');
+    },
+
+    /** @override */
+    removeZoomLevel: function(host) {
+      chrome.send('removeZoomLevel', [host]);
+    },
   };
 
   return {

chrome/browser/resources/settings/site_settings/zoom_levels.html

+<link rel="import" href="chrome://resources/html/polymer.html">
+<link rel="import" href="chrome://resources/cr_elements/icons.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
+<link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
+<link rel="import" href="/i18n_setup.html">
+<link rel="import" href="/settings_shared_css.html">
+<link rel="import" href="/site_settings/site_settings_behavior.html">
+<link rel="import" href="/site_settings/site_settings_prefs_browser_proxy.html">
+
+<dom-module id="zoom-levels">
+  <template>
+    <style include="settings-shared">
+      :host {
+        display: block;
+      }
+
+      .empty-message {
+        margin-top: 15px;
+      }
+    </style>
+    <div class="list-frame vertical-list" id="listContainer">
+      <template is="dom-repeat" items="[[sites_]]" id="list"
+          rendered-item-count="{{renderedCount}}">
+        <div class="list-item">
+          <div class="favicon-image"
+              style$="[[computeSiteIcon(item.origin)]]">
+          </div>
+          <div class="middle">
+            <div>[[item.origin]]</div>
+          </div>
+          <div>[[item.zoom]]</div>
+          <div>
+            <paper-icon-button icon="settings:delete"
+                on-tap="removeZoomLevel_">
+          </div>
+        </div>
+      </template>
+      <template is="dom-if" if="{{!renderedCount}}">
+        <div class="empty-message" id="empty">
+          $i18n{siteSettingsNoZoomedSites}
+        </div>
+      </template>
+    </div>
+  </template>
+  <script src="zoom_levels.js"></script>
+</dom-module>

chrome/browser/resources/settings/site_settings/zoom_levels.js

+// Copyright 2016 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.
+
+/**
+ * @fileoverview
+ * 'zoom-levels' is the polymer element for showing the sites that are zoomed in
+ * or out.
+ */
+
+Polymer({
+  is: 'zoom-levels',
+
+  behaviors: [SiteSettingsBehavior, WebUIListenerBehavior],
+
+  properties: {
+    /**
+     * Array of sites that are zoomed in or out.
+     * @type {!Array<ZoomLevelEntry>}
+     */
+    sites_: Array,
+  },
+
+  ready: function() {
+    this.addWebUIListener('onZoomLevelsChanged',
+        this.onZoomLevelsChanged_.bind(this));
+    this.browserProxy.fetchZoomLevels();
+  },
+
+  /**
+   * A handler for when zoom levels change.
+   * @param {!Array<ZoomLevelEntry>} sites The up to date list of sites and
+   *     their zoom levels.
+   */
+  onZoomLevelsChanged_: function(sites) {
+    this.sites_ = sites;
+  },
+
+  /**
+   * A handler for when a zoom level for a site is deleted.
+   * @param {!{model: !{index: number}}} event
+   * @private
+   */
+   removeZoomLevel_: function(event) {
+     var site = this.sites_[event.model.index];
+     this.browserProxy.removeZoomLevel(site.origin);
+  },
+});

chrome/browser/resources/settings/site_settings_page/site_settings_page.html

@@ -159,6 +159,14 @@
         <div id="handlers" class="secondary"></div>
       </div>
     </div>
+    <div class="settings-box" category$="[[ContentSettingsTypes.ZOOM_LEVELS]]"
+        on-tap="onTapCategory">
+      <iron-icon icon="[[computeIconForContentCategory(
+          ContentSettingsTypes.ZOOM_LEVELS)]]"></iron-icon>
+      <div class="middle">
+        [[computeTitleForContentCategory(ContentSettingsTypes.ZOOM_LEVELS)]]
+      </div>
+    </div>
     <div class="settings-box" category$="[[ContentSettingsTypes.USB_DEVICES]]"
         on-tap="onTapCategory">
       <iron-icon icon="[[computeIconForContentCategory(

chrome/browser/ui/webui/settings/md_settings_localized_strings_provider.cc

@@ -1268,6 +1268,8 @@ void AddSiteSettingsStrings(content::WebUIDataSource* html_source) {
       {"siteSettingsCategoryNotifications",
        IDS_SETTINGS_SITE_SETTINGS_NOTIFICATIONS},
       {"siteSettingsCategoryPopups", IDS_SETTINGS_SITE_SETTINGS_POPUPS},
+      {"siteSettingsCategoryZoomLevels",
+       IDS_SETTINGS_SITE_SETTINGS_ZOOM_LEVELS},
       {"siteSettingsAllSites", IDS_SETTINGS_SITE_SETTINGS_ALL_SITES},
       {"siteSettingsAutomaticDownloads",
        IDS_SETTINGS_SITE_SETTINGS_AUTOMATIC_DOWNLOADS},
@@ -1288,6 +1290,8 @@ void AddSiteSettingsStrings(content::WebUIDataSource* html_source) {
        IDS_SETTINGS_SITE_SETTINGS_UNSANDBOXED_PLUGINS},
       {"siteSettingsUsbDevices", IDS_SETTINGS_SITE_SETTINGS_USB_DEVICES},
       {"siteSettingsFullscreen", IDS_SETTINGS_SITE_SETTINGS_FULLSCREEN},
+      {"siteSettingsZoomLevels", IDS_SETTINGS_SITE_SETTINGS_ZOOM_LEVELS},
+      {"siteSettingsNoZoomedSites", IDS_SETTINGS_SITE_SETTINGS_NO_ZOOMED_SITES},
       {"siteSettingsMaySaveCookies",
        IDS_SETTINGS_SITE_SETTINGS_MAY_SAVE_COOKIES},
       {"siteSettingsAskFirst", IDS_SETTINGS_SITE_SETTINGS_ASK_FIRST},

chrome/browser/ui/webui/settings/site_settings_handler.cc

@@ -9,6 +9,7 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/i18n/number_formatting.h"
 #include "base/macros.h"
 #include "base/values.h"
 #include "chrome/browser/browsing_data/browsing_data_local_storage_helper.h"
@@ -18,16 +19,20 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/site_settings_helper.h"
 #include "chrome/common/extensions/manifest_handlers/app_launch_info.h"
+#include "chrome/grit/generated_resources.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
 #include "components/content_settings/core/common/content_settings_types.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/web_ui.h"
+#include "content/public/common/page_zoom.h"
+#include "content/public/common/url_constants.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/common/permissions/api_permission.h"
 #include "extensions/common/permissions/permissions_data.h"
 #include "storage/browser/quota/quota_manager.h"
 #include "storage/common/quota/quota_status_code.h"
+#include "ui/base/l10n/l10n_util.h"
 #include "ui/base/text/bytes_formatting.h"
 
 namespace settings {
@@ -36,6 +41,7 @@ namespace {
 
 const char kAppName[] = "appName";
 const char kAppId[] = "appId";
+const char kZoom[] = "zoom";
 
 // Return an appropriate API Permission ID for the given string name.
 extensions::APIPermission::APIPermission::ID APIPermissionFromGroupName(
@@ -158,6 +164,14 @@ void SiteSettingsHandler::RegisterMessages() {
       "updateIncognitoStatus",
       base::Bind(&SiteSettingsHandler::HandleUpdateIncognitoStatus,
                  base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "fetchZoomLevels",
+      base::Bind(&SiteSettingsHandler::HandleFetchZoomLevels,
+                 base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "removeZoomLevel",
+      base::Bind(&SiteSettingsHandler::HandleRemoveZoomLevel,
+                 base::Unretained(this)));
 }
 
 void SiteSettingsHandler::OnJavascriptAllowed() {
@@ -175,11 +189,22 @@ void SiteSettingsHandler::OnJavascriptAllowed() {
   notification_registrar_.Add(
       this, chrome::NOTIFICATION_PROFILE_DESTROYED,
       content::NotificationService::AllSources());
+
+  // Here we only subscribe to the HostZoomMap for the default storage partition
+  // since we don't allow the user to manage the zoom levels for apps.
+  // We're only interested in zoom-levels that are persisted, since the user
+  // is given the opportunity to view/delete these in the content-settings page.
+  host_zoom_map_subscription_ =
+      content::HostZoomMap::GetDefaultForBrowserContext(profile_)
+          ->AddZoomLevelChangedCallback(
+              base::Bind(&SiteSettingsHandler::OnZoomLevelChanged,
+                         base::Unretained(this)));
 }
 
 void SiteSettingsHandler::OnJavascriptDisallowed() {
   observer_.RemoveAll();
   notification_registrar_.RemoveAll();
+  host_zoom_map_subscription_.reset();
 }
 
 void SiteSettingsHandler::OnGetUsageInfo(
@@ -265,6 +290,11 @@ void SiteSettingsHandler::Observe(
   }
 }
 
+void SiteSettingsHandler::OnZoomLevelChanged(
+    const content::HostZoomMap::ZoomLevelChange& change) {
+  SendZoomLevels();
+}
+
 void SiteSettingsHandler::HandleFetchUsageTotal(
     const base::ListValue* args) {
   AllowJavascript();
@@ -528,4 +558,92 @@ void SiteSettingsHandler::SendIncognitoStatus(
                          base::FundamentalValue(incognito_enabled));
 }
 
+void SiteSettingsHandler::HandleFetchZoomLevels(const base::ListValue* args) {
+  AllowJavascript();
+  SendZoomLevels();
+}
+
+void SiteSettingsHandler::SendZoomLevels() {
+  if (!IsJavascriptAllowed())
+    return;
+
+  base::ListValue zoom_levels_exceptions;
+
+  content::HostZoomMap* host_zoom_map =
+      content::HostZoomMap::GetDefaultForBrowserContext(profile_);
+  content::HostZoomMap::ZoomLevelVector zoom_levels(
+      host_zoom_map->GetAllZoomLevels());
+
+  // Sort ZoomLevelChanges by host and scheme
+  // (a.com < http://a.com < https://a.com < b.com).
+  std::sort(zoom_levels.begin(), zoom_levels.end(),
+            [](const content::HostZoomMap::ZoomLevelChange& a,
+               const content::HostZoomMap::ZoomLevelChange& b) {
+              return a.host == b.host ? a.scheme < b.scheme : a.host < b.host;
+            });
+
+  for (content::HostZoomMap::ZoomLevelVector::const_iterator i =
+           zoom_levels.begin();
+       i != zoom_levels.end();
+       ++i) {
+    std::unique_ptr<base::DictionaryValue> exception(new base::DictionaryValue);
+    switch (i->mode) {
+      case content::HostZoomMap::ZOOM_CHANGED_FOR_HOST: {
+        std::string host = i->host;
+        if (host == content::kUnreachableWebDataURL) {
+          host =
+              l10n_util::GetStringUTF8(IDS_ZOOMLEVELS_CHROME_ERROR_PAGES_LABEL);
+        }
+        exception->SetString(site_settings::kOrigin, host);
+        break;
+      }
+      case content::HostZoomMap::ZOOM_CHANGED_FOR_SCHEME_AND_HOST:
+        // These are not stored in preferences and get cleared on next browser
+        // start. Therefore, we don't care for them.
+        continue;
+      case content::HostZoomMap::PAGE_SCALE_IS_ONE_CHANGED:
+        continue;
+      case content::HostZoomMap::ZOOM_CHANGED_TEMPORARY_ZOOM:
+        NOTREACHED();
+    }
+
+    std::string setting_string =
+        content_settings::ContentSettingToString(CONTENT_SETTING_DEFAULT);
+    DCHECK(!setting_string.empty());
+
+    exception->SetString(site_settings::kSetting, setting_string);
+
+    // Calculate the zoom percent from the factor. Round up to the nearest whole
+    // number.
+    int zoom_percent = static_cast<int>(
+        content::ZoomLevelToZoomFactor(i->zoom_level) * 100 + 0.5);
+    exception->SetString(kZoom, base::FormatPercent(zoom_percent));
+    exception->SetString(
+        site_settings::kSource, site_settings::kPreferencesSource);
+    // Append the new entry to the list and map.
+    zoom_levels_exceptions.Append(std::move(exception));
+  }
+
+  CallJavascriptFunction("cr.webUIListenerCallback",
+                         base::StringValue("onZoomLevelsChanged"),
+                         zoom_levels_exceptions);
+}
+
+void SiteSettingsHandler::HandleRemoveZoomLevel(const base::ListValue* args) {
+  CHECK_EQ(1U, args->GetSize());
+
+  std::string origin;
+  CHECK(args->GetString(0, &origin));
+
+  if (origin ==
+          l10n_util::GetStringUTF8(IDS_ZOOMLEVELS_CHROME_ERROR_PAGES_LABEL)) {
+    origin = content::kUnreachableWebDataURL;
+  }
+
+  content::HostZoomMap* host_zoom_map;
+  host_zoom_map = content::HostZoomMap::GetDefaultForBrowserContext(profile_);
+  double default_level = host_zoom_map->GetDefaultZoomLevel();
+  host_zoom_map->SetZoomLevelForHost(origin, default_level);
+}
+
 }  // namespace settings

chrome/browser/ui/webui/settings/site_settings_handler.h

@@ -11,6 +11,7 @@
 #include "chrome/browser/storage/storage_info_fetcher.h"
 #include "chrome/browser/ui/webui/settings/settings_page_ui_handler.h"
 #include "components/content_settings/core/browser/content_settings_observer.h"
+#include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
@@ -26,7 +27,7 @@ namespace settings {
 // Chrome "ContentSettings" settings page UI handler.
 class SiteSettingsHandler : public SettingsPageUIHandler,
                             public content_settings::Observer,
-                            public content::NotificationObserver  {
+                            public content::NotificationObserver {
  public:
   explicit SiteSettingsHandler(Profile* profile);
   ~SiteSettingsHandler() override;
@@ -51,12 +52,16 @@ class SiteSettingsHandler : public SettingsPageUIHandler,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
+  // content::HostZoomMap subscription.
+  void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change);
+
  private:
   friend class SiteSettingsHandlerTest;
   FRIEND_TEST_ALL_PREFIXES(SiteSettingsHandlerTest, GetAndSetDefault);
   FRIEND_TEST_ALL_PREFIXES(SiteSettingsHandlerTest, Origins);
   FRIEND_TEST_ALL_PREFIXES(SiteSettingsHandlerTest, Patterns);
   FRIEND_TEST_ALL_PREFIXES(SiteSettingsHandlerTest, Incognito);
+  FRIEND_TEST_ALL_PREFIXES(SiteSettingsHandlerTest, ZoomLevels);
 
   // Asynchronously fetches the usage for a given origin. Replies back with
   // OnGetUsageInfo above.
@@ -91,10 +96,23 @@ class SiteSettingsHandler : public SettingsPageUIHandler,
   // Notifies the JS side whether incognito is enabled.
   void SendIncognitoStatus(Profile* profile, bool was_destroyed);
 
+  // Handles the request for a list of all zoom levels.
+  void HandleFetchZoomLevels(const base::ListValue* args);
+
+  // Sends the zoom level list down to the web ui.
+  void SendZoomLevels();
+
+  // Removes a particular zoom level for a given host.
+  void HandleRemoveZoomLevel(const base::ListValue* args);
+
   Profile* profile_;
 
   content::NotificationRegistrar notification_registrar_;
 
+  // Keeps track of events related to zooming.
+  std::unique_ptr<content::HostZoomMap::Subscription>
+      host_zoom_map_subscription_;
+
   // The host for which to fetch usage.
   std::string usage_host_;
 

chrome/browser/ui/webui/settings/site_settings_handler_unittest.cc

@@ -148,6 +148,37 @@ class SiteSettingsHandlerTest : public testing::Test {
     EXPECT_EQ(expected_incognito, incognito);
   }
 
+  void ValidateZoom(const std::string& expected_host,
+      const std::string& expected_zoom, size_t expected_total_calls) {
+    EXPECT_EQ(expected_total_calls, web_ui()->call_data().size());
+
+    const content::TestWebUI::CallData& data = *web_ui()->call_data().back();
+    EXPECT_EQ("cr.webUIListenerCallback", data.function_name());
+
+    std::string callback_id;
+    ASSERT_TRUE(data.arg1()->GetAsString(&callback_id));
+    EXPECT_EQ("onZoomLevelsChanged", callback_id);
+
+    const base::ListValue* exceptions;
+    ASSERT_TRUE(data.arg2()->GetAsList(&exceptions));
+    if (expected_host.empty()) {
+      EXPECT_EQ(0U, exceptions->GetSize());
+    } else {
+      EXPECT_EQ(1U, exceptions->GetSize());
+
+      const base::DictionaryValue* exception;
+      ASSERT_TRUE(exceptions->GetDictionary(0, &exception));
+
+      std::string host;
+      ASSERT_TRUE(exception->GetString("origin", &host));
+      ASSERT_EQ(expected_host, host);
+
+      std::string zoom;
+      ASSERT_TRUE(exception->GetString("zoom", &zoom));
+      ASSERT_EQ(expected_zoom, zoom);
+    }
+  }
+
   void CreateIncognitoProfile() {
     incognito_profile_ = TestingProfile::Builder().BuildIncognito(&profile_);
   }
@@ -253,4 +284,26 @@ TEST_F(SiteSettingsHandlerTest, Incognito) {
   ValidateIncognitoExists(false, 3U);
 }
 
+TEST_F(SiteSettingsHandlerTest, ZoomLevels) {
+  std::string host("http://www.google.com");
+  double zoom_level = 1.1;
+
+  content::HostZoomMap* host_zoom_map =
+      content::HostZoomMap::GetDefaultForBrowserContext(profile());
+  host_zoom_map->SetZoomLevelForHost(host, zoom_level);
+  ValidateZoom(host, "122%", 1U);
+
+  base::ListValue args;
+  handler()->HandleFetchZoomLevels(&args);
+  ValidateZoom(host, "122%", 2U);
+
+  args.AppendString("http://www.google.com");
+  handler()->HandleRemoveZoomLevel(&args);
+  ValidateZoom("", "", 3U);
+
+  double default_level = host_zoom_map->GetDefaultZoomLevel();
+  double level = host_zoom_map->GetZoomLevelForHostAndScheme("http", host);
+  EXPECT_EQ(default_level, level);
+}
+
 }  // namespace settings

chrome/test/data/webui/settings/cr_settings_browsertest.js

@@ -497,6 +497,7 @@ CrSettingsSiteSettingsTest.prototype = {
     'site_settings_category_tests.js',
     'test_browser_proxy.js',
     'test_site_settings_prefs_browser_proxy.js',
+    'zoom_levels_tests.js',
   ]),
 };
 
@@ -505,6 +506,7 @@ TEST_F('CrSettingsSiteSettingsTest', 'SiteSettings', function() {
   site_details_permission.registerTests();
   site_list.registerTests();
   site_settings_category.registerTests();
+  zoom_levels.registerTests();
 
   mocha.run();
 });

chrome/test/data/webui/settings/site_settings_category_tests.js

@@ -144,7 +144,8 @@ cr.define('site_settings_category', function() {
           // Test category text ids and descriptions for those categories that
           // have those.
           if (category != settings.ContentSettingsTypes.FULLSCREEN &&
-              category != settings.ContentSettingsTypes.USB_DEVICES) {
+              category != settings.ContentSettingsTypes.USB_DEVICES &&
+              category != settings.ContentSettingsTypes.ZOOM_LEVELS) {
             assertNotEquals('', testElement.computeCategoryTextId(category));
 
             assertNotEquals('', testElement.computeCategoryDesc(

chrome/test/data/webui/settings/test_site_settings_prefs_browser_proxy.js

@@ -50,8 +50,10 @@ var prefsEmpty = {
  */
 var TestSiteSettingsPrefsBrowserProxy = function() {
   settings.TestBrowserProxy.call(this, [
+    'fetchZoomLevels',
     'getDefaultValueForContentType',
     'getExceptionList',
+    'removeZoomLevel',
     'resetCategoryPermissionForOrigin',
     'setCategoryPermissionForOrigin',
     'setDefaultValueForContentType',
@@ -59,10 +61,11 @@ var TestSiteSettingsPrefsBrowserProxy = function() {
 
   /** @private {!SiteSettingsPref} */
   this.prefs_ = prefsEmpty;
+
+  /** @private {!Array<ZoomLevelEntry>} */
+  this.zoomList_ = [];
 };
 
-// TODO(finnur): Modify the tests so that most of the code this class implements
-//     can be ripped out.
 TestSiteSettingsPrefsBrowserProxy.prototype = {
   __proto__: settings.TestBrowserProxy.prototype,
 
@@ -82,6 +85,14 @@ TestSiteSettingsPrefsBrowserProxy.prototype = {
     }
   },
 
+  /**
+   * Sets the prefs to use when testing.
+   * @param !Array<ZoomLevelEntry> list The zoom list to set.
+   */
+  setZoomList: function(list) {
+    this.zoomList_ = list;
+  },
+
   /** @override */
   setDefaultValueForContentType: function(contentType, defaultValue) {
     this.methodCalled(
@@ -185,4 +196,15 @@ TestSiteSettingsPrefsBrowserProxy.prototype = {
         [primaryPattern, secondaryPattern, contentType, value]);
     return Promise.resolve();
   },
+
+  /** @override */
+  fetchZoomLevels: function() {
+    cr.webUIListenerCallback('onZoomLevelsChanged', this.zoomList_);
+    this.methodCalled('fetchZoomLevels');
+  },
+
+  /** @override */
+  removeZoomLevel: function(host) {
+    this.methodCalled('removeZoomLevel', [host]);
+  },
 };

chrome/test/data/webui/settings/zoom_levels_tests.js

+// Copyright 2016 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.
+
+/** @fileoverview Suite of tests for zoom-levels. */
+cr.define('zoom_levels', function() {
+  function registerTests() {
+    suite('ZoomLevels', function() {
+      /**
+       * A zoom levels category created before each test.
+       * @type {ZoomLevels}
+       */
+      var testElement;
+
+      /**
+       * The mock proxy object to use during test.
+       * @type {TestSiteSettingsPrefsBrowserProxy}
+       */
+      var browserProxy = null;
+
+      /**
+       * An example zoom list.
+       * @type {!Array<ZoomLevelEntry>}
+       */
+      var zoomList = [
+          {
+            origin: 'http://www.google.com',
+            setting: '',
+            source: '',
+            zoom: '125%',
+          },
+          {
+            origin: 'http://www.chromium.org',
+            setting: '',
+            source: '',
+            zoom: '125%',
+          },
+      ];
+
+      // Import necessary html before running suite.
+      suiteSetup(function() {
+        return PolymerTest.importHtml(
+           'chrome://md-settings/site_settings/zoom_levels.html');
+      });
+
+      setup(function() {
+        browserProxy = new TestSiteSettingsPrefsBrowserProxy();
+        settings.SiteSettingsPrefsBrowserProxyImpl.instance_ = browserProxy;
+        return initPage();
+      });
+
+      teardown(function() {
+        testElement.remove();
+        testElement = null;
+      });
+
+      /** @return {!Promise} */
+      function initPage() {
+        browserProxy.reset();
+        PolymerTest.clearBody();
+        testElement = document.createElement('zoom-levels');
+        document.body.appendChild(testElement);
+        return browserProxy.whenCalled('fetchZoomLevels');
+      }
+
+      /**
+       * Fetch the remove button from the list.
+       * @param {!HTMLElement} listContainer The list to use for the lookup.
+       * @param {number} index The index of the child element (which site) to
+       *     fetch.
+       */
+      function getRemoveButton(listContainer, index) {
+        return listContainer.children[index].querySelector('paper-icon-button');
+      }
+
+      test('empty zoom state', function() {
+        var list = testElement.$.list;
+        assertTrue(!!list);
+        assertEquals(0, list.items.length);
+      });
+
+      test('non-empty zoom state', function() {
+        browserProxy.setZoomList(zoomList);
+
+        return initPage().then(function() {
+          var list = testElement.$.list;
+          assertTrue(!!list);
+          assertEquals(2, list.items.length);
+
+          var removeButton =
+              getRemoveButton(testElement.$.listContainer, 0);
+          assert(!!removeButton);
+          MockInteractions.tap(removeButton);
+          return browserProxy.whenCalled('removeZoomLevel');
+        }).then(function(arguments) {
+          assertEquals("http://www.google.com", arguments[0]);
+        });
+      });
+    });
+  }
+
+  return {
+    registerTests: registerTests,
+  };
+});