Start upstreaming accessibility.

BUG=http://crbug.com/138218


Review URL: https://chromiumcodereview.appspot.com/10832104

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149667 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 570 insertions, 9 deletions

diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentView.java b/content/public/android/java/src/org/chromium/content/browser/ContentView.java
index d8501ec..6e796fa 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentView.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentView.java
@@ -7,13 +7,18 @@ package org.chromium.content.browser;
 import android.content.Context;
 import android.content.res.Configuration;
 import android.graphics.Canvas;
+import android.os.Build;
 import android.util.AttributeSet;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityNodeInfo;
 import android.webkit.DownloadListener;
 import android.widget.FrameLayout;
 
+import org.chromium.content.browser.ContentViewCore;
+
 /**
  * The containing view for {@link ContentViewCore} that exists in the Android UI hierarchy and
  * exposes the various {@link View} functionality to it.
@@ -94,21 +99,55 @@ public class ContentView extends FrameLayout implements ContentViewCore.Internal
 
     private ContentViewCore mContentViewCore;
 
-    public ContentView(Context context, int nativeWebContents, int personality) {
-        this(context, nativeWebContents, null, android.R.attr.webViewStyle, personality);
+    /**
+     * Creates an instance of a ContentView.
+     * @param context The Context the view is running in, through which it can
+     *                access the current theme, resources, etc.
+     * @param nativeWebContents A pointer to the native web contents.
+     * @param personality One of {@link #PERSONALITY_CHROME} or {@link #PERSONALITY_VIEW}.
+     * @return A ContentView instance.
+     */
+    public static ContentView newInstance(Context context, int nativeWebContents, int personality) {
+        return newInstance(context, nativeWebContents, null, android.R.attr.webViewStyle,
+                personality);
     }
 
-    public ContentView(Context context, int nativeWebContents, AttributeSet attrs) {
+    /**
+     * Creates an instance of a ContentView.
+     * @param context The Context the view is running in, through which it can
+     *                access the current theme, resources, etc.
+     * @param nativeWebContents A pointer to the native web contents.
+     * @param attrs The attributes of the XML tag that is inflating the view.
+     * @return A ContentView instance.
+     */
+    public static ContentView newInstance(Context context, int nativeWebContents,
+            AttributeSet attrs) {
         // TODO(klobag): use the WebViewStyle as the default style for now. It enables scrollbar.
         // When ContentView is moved to framework, we can define its own style in the res.
-        this(context, nativeWebContents, attrs, android.R.attr.webViewStyle);
+        return newInstance(context, nativeWebContents, attrs, android.R.attr.webViewStyle);
+    }
+
+    /**
+     * Creates an instance of a ContentView.
+     * @param context The Context the view is running in, through which it can
+     *                access the current theme, resources, etc.
+     * @param nativeWebContents A pointer to the native web contents.
+     * @param attrs The attributes of the XML tag that is inflating the view.
+     * @param defStyle The default style to apply to this view.
+     * @return A ContentView instance.
+     */
+    public static ContentView newInstance(Context context, int nativeWebContents,
+            AttributeSet attrs, int defStyle) {
+        return newInstance(context, nativeWebContents, attrs, defStyle, PERSONALITY_VIEW);
     }
 
-    public ContentView(Context context, int nativeWebContents, AttributeSet attrs, int defStyle) {
-        this(context, nativeWebContents, attrs, defStyle, PERSONALITY_VIEW);
+    private static ContentView newInstance(Context context, int nativeWebContents,
+            AttributeSet attrs, int defStyle, int personality) {
+        // TODO(dtrainor): Upstream JellyBean version of AccessibilityInjector when SDK is 16.
+        return new ContentView(context, nativeWebContents, attrs, defStyle, personality);
     }
 
-    private ContentView(Context context, int nativeWebContents, AttributeSet attrs, int defStyle,
+    protected ContentView(Context context, int nativeWebContents, AttributeSet attrs, int defStyle,
             int personality) {
         super(context, attrs, defStyle);
 
@@ -320,6 +359,34 @@ public class ContentView extends FrameLayout implements ContentViewCore.Internal
     }
 
     /**
+     * This method should be called when the containing activity is paused.
+     **/
+    public void onActivityPause() {
+        mContentViewCore.onActivityPause();
+    }
+
+    /**
+     * This method should be called when the containing activity is resumed.
+     **/
+    public void onActivityResume() {
+        mContentViewCore.onActivityResume();
+    }
+
+    /**
+     * To be called when the ContentView is shown.
+     **/
+    public void onShow() {
+        mContentViewCore.onShow();
+    }
+
+    /**
+     * To be called when the ContentView is hidden.
+     **/
+    public void onHide() {
+        mContentViewCore.onHide();
+    }
+
+    /**
      * Return the ContentSettings object used to control the settings for this
      * WebView.
      *
@@ -363,6 +430,30 @@ public class ContentView extends FrameLayout implements ContentViewCore.Internal
         return super.awakenScrollBars();
     }
 
+    @Override
+    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
+        super.onInitializeAccessibilityNodeInfo(info);
+        mContentViewCore.onInitializeAccessibilityNodeInfo(info);
+    }
+
+    @Override
+    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
+        super.onInitializeAccessibilityEvent(event);
+        mContentViewCore.onInitializeAccessibilityEvent(event);
+    }
+
+    @Override
+    protected void onAttachedToWindow() {
+        super.onAttachedToWindow();
+        mContentViewCore.onAttachedToWindow();
+    }
+
+    @Override
+    protected void onDetachedFromWindow() {
+        super.onDetachedFromWindow();
+        mContentViewCore.onDetachedFromWindow();
+    }
+
     void updateMultiTouchZoomSupport() {
         mContentViewCore.updateMultiTouchZoomSupport();
     }
diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
index 06c035f..f1c48e9 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
@@ -7,6 +7,7 @@ package org.chromium.content.browser;
 import android.content.Context;
 import android.content.res.Configuration;
 import android.graphics.Canvas;
+import android.os.Build;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.ActionMode;
@@ -14,6 +15,8 @@ import android.view.KeyEvent;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityNodeInfo;
 import android.webkit.DownloadListener;
 
 import org.chromium.base.CalledByNative;
@@ -25,6 +28,7 @@ import org.chromium.content.browser.ZoomManager;
 import org.chromium.content.common.CleanupReference;
 import org.chromium.content.common.TraceEvent;
 
+import org.chromium.content.browser.accessibility.AccessibilityInjector;
 import org.chromium.content.browser.ContentViewGestureHandler.MotionEventDelegate;
 
 /**
@@ -178,6 +182,9 @@ public class ContentViewCore implements MotionEventDelegate {
     // over DownloadListener.
     private ContentViewDownloadDelegate mDownloadDelegate;
 
+    // The AccessibilityInjector that handles loading Accessibility scripts into the web page.
+    private final AccessibilityInjector mAccessibilityInjector;
+
     /**
      * Enable multi-process ContentView. This should be called by the application before
      * constructing any ContentView instances. If enabled, ContentView will run renderers in
@@ -235,6 +242,9 @@ public class ContentViewCore implements MotionEventDelegate {
         AndroidBrowserProcess.initContentViewProcess(
                 context, AndroidBrowserProcess.MAX_RENDERERS_SINGLE_PROCESS);
 
+        mAccessibilityInjector = AccessibilityInjector.newInstance(this);
+        mAccessibilityInjector.addOrRemoveAccessibilityApisIfNecessary();
+
         initialize(context, nativeWebContents, personality);
     }
 
@@ -368,6 +378,7 @@ public class ContentViewCore implements MotionEventDelegate {
      *                       omnibox can report suggestions correctly.
      */
     public void loadUrlWithoutUrlSanitization(String url, int pageTransition) {
+        mAccessibilityInjector.addOrRemoveAccessibilityApisIfNecessary();
         if (mNativeContentViewCore != 0) {
             if (isPersonalityView()) {
                 nativeLoadUrlWithoutUrlSanitizationWithUserAgentOverride(
@@ -484,6 +495,7 @@ public class ContentViewCore implements MotionEventDelegate {
      * Reload the current page.
      */
     public void reload() {
+        mAccessibilityInjector.addOrRemoveAccessibilityApisIfNecessary();
         if (mNativeContentViewCore != 0) nativeReload(mNativeContentViewCore);
     }
 
@@ -605,19 +617,35 @@ public class ContentViewCore implements MotionEventDelegate {
     }
 
     /**
-     * This method should be called when the containing activity is paused
+     * This method should be called when the containing activity is paused.
      */
     public void onActivityPause() {
         TraceEvent.begin();
         hidePopupDialog();
+        setAccessibilityState(false);
         TraceEvent.end();
     }
 
     /**
-     * Called when the ContentView is hidden.
+     * This method should be called when the containing activity is resumed.
+     */
+    public void onActivityResume() {
+        setAccessibilityState(true);
+    }
+
+    /**
+     * To be called when the ContentView is shown.
+     */
+    public void onShow() {
+        setAccessibilityState(true);
+    }
+
+    /**
+     * To be called when the ContentView is hidden.
      */
     public void onHide() {
         hidePopupDialog();
+        setAccessibilityState(false);
     }
 
     /**
@@ -645,6 +673,22 @@ public class ContentViewCore implements MotionEventDelegate {
         SelectPopupDialog.hide(this);
     }
 
+    /**
+     * @see View#onAttachedToWindow()
+     */
+    @SuppressWarnings("javadoc")
+    protected void onAttachedToWindow() {
+        setAccessibilityState(true);
+    }
+
+    /**
+     * @see View#onDetachedFromWindow()
+     */
+    @SuppressWarnings("javadoc")
+    protected void onDetachedFromWindow() {
+        setAccessibilityState(false);
+    }
+
     // End FrameLayout overrides.
 
     /**
@@ -1012,6 +1056,57 @@ public class ContentViewCore implements MotionEventDelegate {
         getContentViewClient().onStartContentIntent(getContext(), contentUrl);
     }
 
+    /**
+     * Determines whether or not this ContentViewCore can handle this accessibility action.
+     * @param action The action to perform.
+     * @return Whether or not this action is supported.
+     */
+    public boolean supportsAccessibilityAction(int action) {
+        return mAccessibilityInjector.supportsAccessibilityAction(action);
+    }
+
+    /**
+     * Attempts to perform an accessibility action on the web content.  If the accessibility action
+     * cannot be processed, it returns {@code null}, allowing the caller to know to call the
+     * super {@link View#performAccessibilityAction(int, Bundle)} method and use that return value.
+     * Otherwise the return value from this method should be used.
+     * @param action The action to perform.
+     * @param arguments Optional action arguments.
+     * @return Whether the action was performed or {@code null} if the call should be delegated to
+     *         the super {@link View} class.
+     */
+    public boolean performAccessibilityAction(int action, Bundle arguments) {
+        if (mAccessibilityInjector.supportsAccessibilityAction(action)) {
+            return mAccessibilityInjector.performAccessibilityAction(action, arguments);
+        }
+
+        return false;
+    }
+
+    /**
+     * @see View#onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo)
+     */
+    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
+        mAccessibilityInjector.onInitializeAccessibilityNodeInfo(info);
+
+        // TODO(dtrainor): Upstream accessibility scrolling event information once that data is
+        // available in ContentViewCore.  Currently internal scrolling variables aren't upstreamed.
+    }
+
+    /**
+     * @see View#onInitializeAccessibilityEvent(AccessibilityEvent)
+     */
+    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
+        event.setClassName(this.getClass().getName());
+    }
+
+    /**
+     * Enable or disable accessibility features.
+     */
+    public void setAccessibilityState(boolean state) {
+        mAccessibilityInjector.setScriptEnabled(state);
+    }
+
     // The following methods are implemented at native side.
 
     /**
diff --git a/content/public/android/java/src/org/chromium/content/browser/accessibility/AccessibilityInjector.java b/content/public/android/java/src/org/chromium/content/browser/accessibility/AccessibilityInjector.java
new file mode 100644
index 0000000..9127ae4
--- /dev/null
+++ b/content/public/android/java/src/org/chromium/content/browser/accessibility/AccessibilityInjector.java
@@ -0,0 +1,375 @@
+// 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.
+
+package org.chromium.content.browser.accessibility;
+
+import android.content.Context;
+import android.os.Build;
+import android.os.Bundle;
+import android.os.SystemClock;
+import android.os.Vibrator;
+import android.provider.Settings;
+import android.speech.tts.TextToSpeech;
+import android.view.View;
+import android.view.accessibility.AccessibilityManager;
+import android.view.accessibility.AccessibilityNodeInfo;
+
+import org.apache.http.NameValuePair;
+import org.apache.http.client.utils.URLEncodedUtils;
+import org.chromium.content.browser.ContentViewCore;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.lang.reflect.Field;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Responsible for accessibility injection and management of a {@link ContentViewCore}.
+ */
+public class AccessibilityInjector {
+    // The ContentView this injector is responsible for managing.
+    protected ContentViewCore mContentViewCore;
+
+    // The Java objects that are exposed to JavaScript
+    private TextToSpeechWrapper mTextToSpeech;
+    private VibratorWrapper mVibrator;
+
+    // Lazily loaded helper objects.
+    private AccessibilityManager mAccessibilityManager;
+
+    // Whether or not we should be injecting the script.
+    protected boolean mInjectedScriptEnabled;
+    protected boolean mScriptInjected;
+
+    // constants for determining script injection strategy
+    private static final int ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED = -1;
+    private static final int ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT = 0;
+    private static final int ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED = 1;
+    private static final String ALIAS_ACCESSIBILITY_JS_INTERFACE = "accessibility";
+    private static final String ALIAS_ACCESSIBILITY_JS_INTERFACE_2 = "accessibility2";
+
+    // Template for JavaScript that injects a screen-reader.
+    private static final String ACCESSIBILITY_SCREEN_READER_URL =
+            "https://ssl.gstatic.com/accessibility/javascript/android/chromeandroidvox.js";
+
+    private static final String ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE =
+            "(function() {" +
+            "    var chooser = document.createElement('script');" +
+            "    chooser.type = 'text/javascript';" +
+            "    chooser.src = '%1s';" +
+            "    document.getElementsByTagName('head')[0].appendChild(chooser);" +
+            "  })();";
+
+    // JavaScript call to turn ChromeVox on or off.
+    private static final String TOGGLE_CHROME_VOX_JAVASCRIPT =
+            "(function() {" +
+            "    if (typeof cvox !== 'undefined') {" +
+            "        cvox.ChromeVox.host.activateOrDeactivateChromeVox(%1s);" +
+            "    }" +
+            "  })();";
+
+    /**
+     * Returns an instance of the {@link AccessibilityInjector} based on the SDK version.
+     * @param view The ContentViewCore that this AccessibilityInjector manages.
+     * @return An instance of a {@link AccessibilityInjector}.
+     */
+    public static AccessibilityInjector newInstance(ContentViewCore view) {
+        // TODO(dtrainor): Upstream JellyBean version of AccessibilityInjector when SDK is 16.
+        return new AccessibilityInjector(view);
+    }
+
+    /**
+     * Creates an instance of the IceCreamSandwichAccessibilityInjector.
+     * @param view The ContentViewCore that this AccessibilityInjector manages.
+     */
+    protected AccessibilityInjector(ContentViewCore view) {
+        mContentViewCore = view;
+    }
+
+    /**
+     * Injects a <script> tag into the current web site that pulls in the ChromeVox script for
+     * accessibility support.  Only injects if accessibility is turned on by
+     * {@link AccessibilityManager#isEnabled()}, accessibility script injection is turned on, and
+     * javascript is enabled on this page.
+     *
+     * @see AccessibilityManager#isEnabled()
+     */
+    public void injectAccessibilityScriptIntoPage() {
+        if (!accessibilityIsAvailable()) return;
+
+        int axsParameterValue = getAxsUrlParameterValue();
+        if (axsParameterValue == ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED) {
+            try {
+                Field field = Settings.Secure.class.getField("ACCESSIBILITY_SCRIPT_INJECTION");
+                field.setAccessible(true);
+                String ACCESSIBILITY_SCRIPT_INJECTION = (String) field.get(null);
+
+                boolean onDeviceScriptInjectionEnabled = (Settings.Secure.getInt(
+                        mContentViewCore.getContext().getContentResolver(),
+                        ACCESSIBILITY_SCRIPT_INJECTION, 0) == 1);
+                String js = getScreenReaderInjectingJs();
+
+                if (onDeviceScriptInjectionEnabled && js != null && mContentViewCore.isAlive()) {
+                    addOrRemoveAccessibilityApisIfNecessary();
+                    mContentViewCore.evaluateJavaScript(js);
+                    mInjectedScriptEnabled = true;
+                    mScriptInjected = true;
+                }
+            } catch (NoSuchFieldException ex) {
+            } catch (IllegalArgumentException ex) {
+            } catch (IllegalAccessException ex) {
+            }
+        }
+    }
+
+    /**
+     * Handles adding or removing accessibility related Java objects ({@link TextToSpeech} and
+     * {@link Vibrator}) interfaces from Javascript.  This method should be called at a time when it
+     * is safe to add or remove these interfaces, specifically when the {@link ContentView} is first
+     * initialized or right before the {@link ContentView} is about to navigate to a URL or reload.
+     * <p>
+     * If this method is called at other times, the interfaces might not be correctly removed,
+     * meaning that Javascript can still access these Java objects that may have been already
+     * shut down.
+     */
+    public void addOrRemoveAccessibilityApisIfNecessary() {
+        if (accessibilityIsAvailable()) {
+            addAccessibilityApis();
+        } else {
+            removeAccessibilityApis();
+        }
+    }
+
+    /**
+     * Checks whether or not touch to explore is enabled on the system.
+     */
+    public boolean accessibilityIsAvailable() {
+        return getAccessibilityManager().isEnabled() &&
+                mContentViewCore.getContentSettings() != null &&
+                mContentViewCore.getContentSettings().getJavaScriptEnabled();
+    }
+
+    /**
+     * Sets whether or not the script is enabled.  If the script is disabled, we also stop any
+     * we output that is occurring.
+     * @param enabled Whether or not to enable the script.
+     */
+    public void setScriptEnabled(boolean enabled) {
+        if (!accessibilityIsAvailable() || mInjectedScriptEnabled == enabled) return;
+
+        mInjectedScriptEnabled = enabled;
+        if (mContentViewCore.isAlive()) {
+            String js = String.format(TOGGLE_CHROME_VOX_JAVASCRIPT, Boolean.toString(
+                    mInjectedScriptEnabled));
+            mContentViewCore.evaluateJavaScript(js);
+
+            if (!mInjectedScriptEnabled) {
+                // Stop any TTS/Vibration right now.
+                onPageLostFocus();
+            }
+        }
+    }
+
+    /**
+     * Notifies this handler that a page load has started, which means we should mark the
+     * accessibility script as not being injected.  This way we can properly ignore incoming
+     * accessibility gesture events.
+     */
+    public void onPageLoadStarted() {
+        mScriptInjected = false;
+    }
+
+    /**
+     * Stop any notifications that are currently going on (e.g. Text-to-Speech).
+     */
+    public void onPageLostFocus() {
+        if (mContentViewCore.isAlive()) {
+            if (mTextToSpeech != null) mTextToSpeech.stop();
+            if (mVibrator != null) mVibrator.cancel();
+        }
+    }
+
+    /**
+     * Initializes an {@link AccessibilityNodeInfo} with the actions and movement granularity
+     * levels supported by this {@link AccessibilityInjector}.
+     * <p>
+     * If an action identifier is added in this method, this {@link AccessibilityInjector} should
+     * also return {@code true} from {@link #supportsAccessibilityAction(int)}.
+     * </p>
+     *
+     * @param info The info to initialize.
+     * @see View#onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo)
+     */
+    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { }
+
+    /**
+     * Returns {@code true} if this {@link AccessibilityInjector} should handle the specified
+     * action.
+     *
+     * @param action An accessibility action identifier.
+     * @return {@code true} if this {@link AccessibilityInjector} should handle the specified
+     *         action.
+     */
+    public boolean supportsAccessibilityAction(int action) {
+        return false;
+    }
+
+    /**
+     * Performs the specified accessibility action.
+     *
+     * @param action The identifier of the action to perform.
+     * @param arguments The action arguments, or {@code null} if no arguments.
+     * @return {@code true} if the action was successful.
+     * @see View#performAccessibilityAction(int, Bundle)
+     */
+    public boolean performAccessibilityAction(int action, Bundle arguments) {
+        return false;
+    }
+
+    protected void addAccessibilityApis() {
+        Context context = mContentViewCore.getContext();
+        if (context != null) {
+            // Enabled, we should try to add if we have to.
+            if (mTextToSpeech == null) {
+                mTextToSpeech = new TextToSpeechWrapper(context);
+                mContentViewCore.addJavascriptInterface(mTextToSpeech,
+                        ALIAS_ACCESSIBILITY_JS_INTERFACE, false);
+            }
+
+            if (mVibrator == null) {
+                mVibrator = new VibratorWrapper(context);
+                mContentViewCore.addJavascriptInterface(mVibrator,
+                        ALIAS_ACCESSIBILITY_JS_INTERFACE_2, false);
+            }
+        }
+    }
+
+    protected void removeAccessibilityApis() {
+        if (mTextToSpeech != null) {
+            mContentViewCore.removeJavascriptInterface(ALIAS_ACCESSIBILITY_JS_INTERFACE);
+            mTextToSpeech.stop();
+            mTextToSpeech.shutdownInternal();
+            mTextToSpeech = null;
+        }
+
+        if (mVibrator != null) {
+            mContentViewCore.removeJavascriptInterface(ALIAS_ACCESSIBILITY_JS_INTERFACE_2);
+            mVibrator.cancel();
+            mVibrator = null;
+        }
+    }
+
+    private int getAxsUrlParameterValue() {
+        if (mContentViewCore.getUrl() == null) return ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED;
+
+        try {
+            List<NameValuePair> params = URLEncodedUtils.parse(new URI(mContentViewCore.getUrl()),
+                    null);
+
+            for (NameValuePair param : params) {
+                if ("axs".equals(param.getName())) {
+                    return Integer.parseInt(param.getValue());
+                }
+            }
+        } catch (URISyntaxException ex) {
+        } catch (NumberFormatException ex) {
+        } catch (IllegalArgumentException ex) {
+        }
+
+        return ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED;
+    }
+
+    private String getScreenReaderInjectingJs() {
+        return String.format(ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE,
+                ACCESSIBILITY_SCREEN_READER_URL);
+    }
+
+    private AccessibilityManager getAccessibilityManager() {
+        if (mAccessibilityManager == null) {
+            mAccessibilityManager = (AccessibilityManager) mContentViewCore.getContext().
+                    getSystemService(Context.ACCESSIBILITY_SERVICE);
+        }
+
+        return mAccessibilityManager;
+    }
+
+    /**
+     * Used to protect how long JavaScript can vibrate for.  This isn't a good comprehensive
+     * protection, just used to cover mistakes and protect against long vibrate durations/repeats.
+     *
+     * Also only exposes methods we *want* to expose, no others for the class.
+     */
+    private static class VibratorWrapper {
+        private static final long MAX_VIBRATE_DURATION_MS = 5000;
+
+        private Vibrator mVibrator;
+
+        public VibratorWrapper(Context context) {
+            mVibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
+        }
+
+        @SuppressWarnings("unused")
+        public boolean hasVibrator() {
+            return mVibrator.hasVibrator();
+        }
+
+        @SuppressWarnings("unused")
+        public void vibrate(long milliseconds) {
+            milliseconds = Math.min(milliseconds, MAX_VIBRATE_DURATION_MS);
+            mVibrator.vibrate(milliseconds);
+        }
+
+        @SuppressWarnings("unused")
+        public void vibrate(long[] pattern, int repeat) {
+            for (int i = 0; i < pattern.length; ++i) {
+                pattern[i] = Math.min(pattern[i], MAX_VIBRATE_DURATION_MS);
+            }
+
+            repeat = -1;
+
+            mVibrator.vibrate(pattern, repeat);
+        }
+
+        @SuppressWarnings("unused")
+        public void cancel() {
+            mVibrator.cancel();
+        }
+    }
+
+    /**
+     * Used to protect the TextToSpeech class, only exposing the methods we want to expose.
+     */
+    private static class TextToSpeechWrapper {
+        private TextToSpeech mTextToSpeech;
+
+        public TextToSpeechWrapper(Context context) {
+            mTextToSpeech = new TextToSpeech(context, null, null);
+        }
+
+        @SuppressWarnings("unused")
+        public boolean isSpeaking() {
+            return mTextToSpeech.isSpeaking();
+        }
+
+        @SuppressWarnings("unused")
+        public int speak(String text, int queueMode, HashMap<String, String> params) {
+            return mTextToSpeech.speak(text, queueMode, params);
+        }
+
+        @SuppressWarnings("unused")
+        public int stop() {
+            return mTextToSpeech.stop();
+        }
+
+        @SuppressWarnings("unused")
+        protected void shutdownInternal() {
+            mTextToSpeech.shutdown();
+        }
+    }
+}