Initial checkin of accessibility extensions.

ui/accessibility/extensions/highcontrast/background.js

+// Copyright (c) 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.
+
+function injectContentScripts() {
+  chrome.windows.getAll({'populate': true}, function(windows) {
+    for (var i = 0; i < windows.length; i++) {
+      var tabs = windows[i].tabs;
+      for (var j = 0; j < tabs.length; j++) {
+        var url = tabs[j].url;
+        if (url.indexOf('chrome') == 0 || url.indexOf('about') == 0) {
+          continue;
+        }
+        chrome.tabs.insertCSS(
+            tabs[j].id,
+            {file: 'highcontrast.css', allFrames: true});
+        chrome.tabs.executeScript(
+            tabs[j].id,
+            {file: 'highcontrast.js', allFrames: true});
+      }
+    }
+  });
+}
+
+function updateTabs() {
+  var msg = {
+    'enabled': getEnabled()
+  };
+  chrome.windows.getAll({'populate': true}, function(windows) {
+    for (var i = 0; i < windows.length; i++) {
+      var tabs = windows[i].tabs;
+      for (var j = 0; j < tabs.length; j++) {
+        var url = tabs[j].url;
+        if (isDisallowedUrl(url)) {
+          continue;
+        }
+        var msg = {
+          'enabled': getEnabled(),
+          'scheme': getSiteScheme(siteFromUrl(url))
+        };
+        chrome.tabs.sendRequest(tabs[j].id, msg);
+      }
+    }
+  });
+}
+
+function toggleEnabled() {
+  setEnabled(!getEnabled());
+  updateTabs();
+}
+
+function toggleSite(url) {
+  var site = siteFromUrl(url);
+  var scheme = getSiteScheme(site);
+  if (scheme > 0) {
+    scheme = 0;
+  } else if (getDefaultScheme() > 0) {
+    scheme = getDefaultScheme();
+  } else {
+    scheme = DEFAULT_SCHEME;
+  }
+  setSiteScheme(site, scheme);
+  updateTabs();
+}
+
+function init() {
+  injectContentScripts();
+  updateTabs();
+
+  chrome.extension.onRequest.addListener(
+      function(request, sender, sendResponse) {
+        if (request['toggle_global']) {
+          toggleEnabled();
+        }
+        if (request['toggle_site']) {
+          toggleSite(sender.tab ? sender.tab.url : 'www.example.com');
+        }
+        if (request['init']) {
+          var scheme = getDefaultScheme();
+          if (sender.tab) {
+            scheme = getSiteScheme(siteFromUrl(sender.tab.url));
+          }
+          var msg = {
+            'enabled': getEnabled(),
+            'scheme': scheme
+          };
+          sendResponse(msg);
+        }
+      });
+
+  document.addEventListener('storage', function(evt) {
+    updateTabs();
+  }, false);
+
+  if (navigator.appVersion.indexOf('Mac') != -1) {
+    chrome.browserAction.setTitle({'title': 'High Contrast (Cmd+Shift+F11)'});
+  }
+}
+
+init();