Initial checkin of accessibility extensions.

ui/accessibility/extensions/alt/background.js

+// 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.
+
+function injectScripts(opt_tab) {
+  chrome.tabs.executeScript({
+    file: 'lib/axs_testing.js',
+    allFrames: true
+  }, function() {
+    console.log('successfully injected axs_testing.js');
+    chrome.tabs.executeScript({
+      file: 'hide-images.js',
+      allFrames: true
+    }, function() {
+      console.log('successfully injected script', opt_tab ? opt_tab.url : '');
+      chrome.tabs.insertCSS({
+        file: 'hide-images.css',
+        allFrames: true
+      }, function() {
+        console.log('successfully injected css', opt_tab ? opt_tab.url : '');
+        chrome.tabs.executeScript({
+          code: 'toggleEnabled();',
+          allFrames: true
+        }, function() {
+          console.log('created infobar');
+          chrome.tabs.executeScript({
+            code: 'createInfobar();'
+          });
+        });
+      });
+    });
+  });
+}
+
+chrome.commands.onCommand.addListener(function(command) {
+  console.log('command: ', command);
+  if (command == 'example_keyboard_command') {
+    injectScripts();
+  }
+});
+
+chrome.browserAction.onClicked.addListener(function(tab) {
+  injectScripts(tab);
+});
+