Native Android accessibility.

content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java

Index: content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java b/content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java
new file mode 100644
index 0000000000000000000000000000000000000000..f0e4c2cd11b0515e0d62c672d6fc9137d6d392df
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+++ b/content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java
@@ -0,0 +1,468 @@
+// Copyright (c) 2013 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.graphics.Rect;
+import android.os.Bundle;
+import android.view.MotionEvent;
+import android.view.View;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityManager;
+import android.view.accessibility.AccessibilityNodeInfo;
+import android.view.accessibility.AccessibilityNodeProvider;
+import android.view.inputmethod.InputMethodManager;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+import org.chromium.content.browser.ContentViewCore;
+import org.chromium.content.browser.RenderCoordinates;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Native accessibility for a {@link ContentViewCore}.
+ */
+@JNINamespace("content")
+public class BrowserAccessibilityManager extends AccessibilityNodeProvider {
+    private static final String TAG = BrowserAccessibilityManager.class.getSimpleName();
+
+    private ContentViewCore mContentViewCore;
+    private AccessibilityManager mAccessibilityManager;
+    private RenderCoordinates mRenderCoordinates;
+    private int mNativeObj;
+    private int mAccessibilityFocusId;
+    private final int[] mTempLocation = new int[2];
+    private View mView;
+    private boolean mUserHasTouchExplored;
+    private boolean mFrameInfoInitialized;
+
+    // If this is true, enables an experimental feature that automatically focuses things
+    // as you explore them. This can be more efficient, but might cause the user to get stuck
+    // on a misbehaving page that keeps stealing focus.
+    private boolean mWebFocusFollowsAccessibilityFocus;
+
+    // If this is true, enables an experimental feature that focuses the web page after it
+    // finishes loading. Disabled for now because it can be confusing if the user was
+    // trying to do something when this happens.
+    private boolean mFocusPageOnLoad;
+
+    /**
+     * Create a BrowserAccessibilityManager object, which is owned by the C++
+     * BrowserAccessibilityManagerAndroid instance, and connects to the content view.
+     * @param nativeBrowserAccessibilityManagerAndroid A pointer to the counterpart native
+     *     C++ object that owns this object.
+     * @param contentViewCore The content view that this object provides accessibility for.
+     */
+    @CalledByNative
+    private static BrowserAccessibilityManager create(int nativeBrowserAccessibilityManagerAndroid,
+            ContentViewCore contentViewCore) {
+        return new BrowserAccessibilityManager(
+            nativeBrowserAccessibilityManagerAndroid, contentViewCore);
+    }
+
+    private BrowserAccessibilityManager(int nativeBrowserAccessibilityManagerAndroid,
+            ContentViewCore contentViewCore) {
+        mNativeObj = nativeBrowserAccessibilityManagerAndroid;
+        mContentViewCore = contentViewCore;
+        mContentViewCore.setBrowserAccessibilityManager(this);
+        mAccessibilityFocusId = View.NO_ID;
+        mView = mContentViewCore.getContainerView();
+        mRenderCoordinates = mContentViewCore.getRenderCoordinates();
+        mAccessibilityManager =
+            (AccessibilityManager) mContentViewCore.getContext()
+            .getSystemService(Context.ACCESSIBILITY_SERVICE);
+    }
+
+    @CalledByNative
+    private void onNativeObjectDestroyed() {
+        if (mContentViewCore.getBrowserAccessibilityManager() == this) {
+            mContentViewCore.setBrowserAccessibilityManager(null);
+        }
+        mNativeObj = 0;
+        mContentViewCore = null;
+    }
+
+    /** @inheritDoc */
+    public AccessibilityNodeInfo createAccessibilityNodeInfo(int virtualViewId) {
+        if (!mAccessibilityManager.isEnabled() || mNativeObj == 0 || !mFrameInfoInitialized) {
+            return null;
+        }
+
+        int rootId = nativeGetRootId(mNativeObj);
+        if (virtualViewId == View.NO_ID) {
+            virtualViewId = rootId;
+        }
+        if (mAccessibilityFocusId == View.NO_ID) {
+            mAccessibilityFocusId = rootId;
+        }
+
+        int nativeNode = nativeGetNativeNodeById(mNativeObj, virtualViewId);
+        if (nativeNode == 0) {
+            return null;
+        }
+
+        final AccessibilityNodeInfo info = AccessibilityNodeInfo.obtain(mView);
+        info.setPackageName(mContentViewCore.getContext().getPackageName());
+        info.setClassName(BrowserAccessibility.nativeGetClassNameJNI(nativeNode));
+        info.setSource(mView, virtualViewId);
+        info.setCheckable(BrowserAccessibility.nativeIsCheckableJNI(nativeNode));
+        info.setChecked(BrowserAccessibility.nativeIsCheckedJNI(nativeNode));
+        info.setEnabled(BrowserAccessibility.nativeIsEnabledJNI(nativeNode));
+        info.setFocused(BrowserAccessibility.nativeIsFocusedJNI(nativeNode));
+        info.setPassword(BrowserAccessibility.nativeIsPasswordJNI(nativeNode));
+        info.setScrollable(BrowserAccessibility.nativeIsScrollableJNI(nativeNode));
+        info.setSelected(BrowserAccessibility.nativeIsSelectedJNI(nativeNode));
+        info.setVisibleToUser(BrowserAccessibility.nativeIsVisibleJNI(nativeNode));
+        info.setContentDescription(BrowserAccessibility.nativeGetNameJNI(nativeNode));
+
+        boolean focusable = BrowserAccessibility.nativeIsFocusableJNI(nativeNode);
+        info.setFocusable(focusable);
+        if (focusable) {
+            if (BrowserAccessibility.nativeIsFocusedJNI(nativeNode))
+                info.addAction(AccessibilityNodeInfo.ACTION_CLEAR_FOCUS);
+            else
+                info.addAction(AccessibilityNodeInfo.ACTION_FOCUS);
+        }
+
+        if (mAccessibilityFocusId == virtualViewId) {
+            info.setAccessibilityFocused(true);
+            info.addAction(AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS);
+        } else {
+            info.setAccessibilityFocused(false);
+            info.addAction(AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS);
+        }
+
+        boolean clickable = BrowserAccessibility.nativeGetClickableJNI(nativeNode);
+        if (clickable)
+            info.addAction(AccessibilityNodeInfo.ACTION_CLICK);
+
+        int childCount = BrowserAccessibility.nativeGetChildCountJNI(nativeNode);
+        for (int i = 0; i < childCount; i++)
+            info.addChild(mView, BrowserAccessibility.nativeGetChildIdAtJNI(nativeNode, i));
+
+
+        if (virtualViewId != rootId)
+            info.setParent(mView, BrowserAccessibility.nativeGetParentJNI(nativeNode));
+
+        Rect boundsInParent = (Rect) BrowserAccessibility.nativeGetRectInParentJNI(nativeNode);
+        if (virtualViewId == rootId) {
+            // Offset of the web content relative to the View.
+            boundsInParent.offset(0, (int) mRenderCoordinates.getContentOffsetYPix());
+        }
+        info.setBoundsInParent(boundsInParent);
+        Rect rect = (Rect) BrowserAccessibility.nativeGetAbsoluteRectJNI(nativeNode);
+
+        // Offset by the scroll position.
+        rect.offset(-(int) mRenderCoordinates.getScrollX(),
+                    -(int) mRenderCoordinates.getScrollY());
+
+        // Convert CSS (web) pixels to Android View pixels
+        rect.left = (int) mRenderCoordinates.fromLocalCssToPix(rect.left);
+        rect.top = (int) mRenderCoordinates.fromLocalCssToPix(rect.top);
+        rect.bottom = (int) mRenderCoordinates.fromLocalCssToPix(rect.bottom);
+        rect.right = (int) mRenderCoordinates.fromLocalCssToPix(rect.right);
+
+        // Offset by the location of the web content within the view.
+        rect.offset(0,
+                    (int) mRenderCoordinates.getContentOffsetYPix());
+
+        // Additionally offset by the location of the view within the screen.
+        final int[] viewLocation = new int[2];
+        mView.getLocationOnScreen(viewLocation);
+        rect.offset(viewLocation[0], viewLocation[1]);
+        info.setBoundsInScreen(rect);
+
+        return info;
+    }
+
+    /** @inheritDoc */
+    public List<AccessibilityNodeInfo> findAccessibilityNodeInfosByText(String text,
+            int virtualViewId) {
+        return new ArrayList<AccessibilityNodeInfo>();
+    }
+
+    /** @inheritDoc */
+    public boolean performAction(int virtualViewId, int action, Bundle arguments) {
+        if (!mAccessibilityManager.isEnabled() || mNativeObj == 0) {
+            return false;
+        }
+
+        int rootId = nativeGetRootId(mNativeObj);
+        int nativeRootNode = nativeGetNativeNodeById(mNativeObj, rootId);
+        int nativeNode = nativeGetNativeNodeById(mNativeObj, virtualViewId);
+        if (nativeNode == 0 || nativeRootNode == 0) {
+            return false;
+        }
+
+        switch (action) {
+            case AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS:
+                if (mAccessibilityFocusId == virtualViewId) {
+                    return true;
+                }
+
+                if (mAccessibilityFocusId != View.NO_ID) {
+                    sendAccessibilityEvent(mAccessibilityFocusId,
+                                           AccessibilityEvent.TYPE_VIEW_HOVER_EXIT);
+                }
+                mAccessibilityFocusId = virtualViewId;
+                focusAndHideOrShowKeyboardIfNecessary(virtualViewId);
+                sendAccessibilityEvent(mAccessibilityFocusId,
+                                       AccessibilityEvent.TYPE_VIEW_HOVER_ENTER);
+                return true;
+            case AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS:
+                if (mAccessibilityFocusId == virtualViewId) {
+                    mAccessibilityFocusId = View.NO_ID;
+                }
+                return true;
+            case AccessibilityNodeInfo.ACTION_CLICK:
+                BrowserAccessibility.nativeClickJNI(nativeNode);
+                break;
+            case AccessibilityNodeInfo.ACTION_FOCUS:
+                BrowserAccessibility.nativeFocusJNI(nativeNode);
+                break;
+            case AccessibilityNodeInfo.ACTION_CLEAR_FOCUS:
+                BrowserAccessibility.nativeFocusJNI(nativeRootNode);
+                break;
+            default:
+                break;
+        }
+        return false;
+    }
+
+    /**
+     * @see View#dispatchHoverEvent(MotionEvent)
+     */
+    public boolean dispatchHoverEvent(MotionEvent event) {
+        if (!mAccessibilityManager.isEnabled() || mNativeObj == 0) {
+            return false;
+        }
+
+        mUserHasTouchExplored = true;
+        float x = event.getX();
+        float y = event.getY();
+
+        // Offset by the location of the web content within the view.
+        // Note: the MotionEvent has view-relative coordinates already,
+        // so we don't have to offset by the view relative to the screen.
+        y -= mRenderCoordinates.getContentOffsetYPix();
+
+        // Convert to CSS coordinates.
+        int cssX = (int) (mRenderCoordinates.fromPixToLocalCss(x) +
+                          mRenderCoordinates.getScrollX());
+        int cssY = (int) (mRenderCoordinates.fromPixToLocalCss(y) +
+                          mRenderCoordinates.getScrollY());
+        int id = nativeHitTest(mNativeObj, cssX, cssY);
+        int nativeNode = nativeGetNativeNodeById(mNativeObj, id);
+        if (nativeNode == 0) {
+            return false;
+        }
+
+        if (mAccessibilityFocusId != id) {
+            mAccessibilityFocusId = id;
+            sendAccessibilityEvent(id, AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
+        }
+
+        // If this is a hover end event, web-focus the element and pop up the keyboard
+        // if necessary.  TODO(aboxhall): figure out what happens when there's an
+        // ACTION_HOVER_EXIT because touch exploration exited the ContentViewCore.
+        if (event.getActionMasked() == MotionEvent.ACTION_HOVER_EXIT) {
+            focusAndHideOrShowKeyboardIfNecessary(id);
+        }
+
+        return true;
+    }
+
+    /**
+     * Called by ContentViewCore to notify us when the frame info is initialized,
+     * the first time, since until that point, we can't use mRenderCoordinates to transform
+     * web coordinates to screen coordinates.
+     */
+    public void notifyFrameInfoInitialized() {
+        if (mFrameInfoInitialized) return;
+
+        mFrameInfoInitialized = true;
+        // (Re-) focus focused element, since we weren't able to create an
+        // AccessibilityNodeInfo for this element before.
+        if (mAccessibilityFocusId != View.NO_ID) {
+            sendAccessibilityEvent(mAccessibilityFocusId,
+                                   AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
+        }
+    }
+
+    private void focusAndHideOrShowKeyboardIfNecessary(int virtualViewId) {
+        // This is an experimental feature. Only do this if enabled.
+        if (!mWebFocusFollowsAccessibilityFocus) {
+            return;
+        }
+
+        int nativeNode = nativeGetNativeNodeById(mNativeObj, virtualViewId);
+        if (nativeNode == 0) {
+            return;
+        }
+
+        InputMethodManager imm =
+                (InputMethodManager) mContentViewCore.getContext().getSystemService(
+                        Context.INPUT_METHOD_SERVICE);
+        if (!BrowserAccessibility.nativeIsFocusableJNI(nativeNode)) {
+            imm.hideSoftInputFromWindow(mView.getWindowToken(),
+                    InputMethodManager.HIDE_IMPLICIT_ONLY);
+            return;
+        }
+
+        if (BrowserAccessibility.nativeIsFocusedJNI(nativeNode)) {
+            return;
+        }
+
+        BrowserAccessibility.nativeFocusJNI(nativeNode);
+        sendAccessibilityEvent(virtualViewId,
+                               AccessibilityEvent.TYPE_VIEW_FOCUSED);
+        // Show/hide keyboard
+        if (BrowserAccessibility.nativeIsEditableTextJNI(nativeNode)) {
+            imm.showSoftInput(mView, InputMethodManager.SHOW_IMPLICIT);
+        } else {
+            imm.hideSoftInputFromWindow(mView.getWindowToken(),
+                                        InputMethodManager.HIDE_IMPLICIT_ONLY);
+        }
+    }
+
+    private void sendAccessibilityEvent(int virtualViewId, int eventType) {
+        if (!mAccessibilityManager.isEnabled() || mNativeObj == 0) return;
+
+        int nativeNode = nativeGetNativeNodeById(mNativeObj, virtualViewId);
+        if (nativeNode == 0) {
+            return;
+        }
+
+        final AccessibilityEvent event = AccessibilityEvent.obtain(eventType);
+        event.setPackageName(mContentViewCore.getContext().getPackageName());
+        event.setClassName(BrowserAccessibility.nativeGetClassNameJNI(nativeNode));
+        event.setChecked(BrowserAccessibility.nativeIsCheckedJNI(nativeNode));
+        event.setEnabled(BrowserAccessibility.nativeIsEnabledJNI(nativeNode));
+        event.setPassword(BrowserAccessibility.nativeIsPasswordJNI(nativeNode));
+        event.setScrollable(BrowserAccessibility.nativeIsScrollableJNI(nativeNode));
+        event.setCurrentItemIndex(BrowserAccessibility.nativeGetItemIndexJNI(nativeNode));
+        event.setItemCount(BrowserAccessibility.nativeGetItemCountJNI(nativeNode));
+        event.setScrollX(BrowserAccessibility.nativeGetScrollXJNI(nativeNode));
+        event.setScrollY(BrowserAccessibility.nativeGetScrollYJNI(nativeNode));
+        event.setMaxScrollX(BrowserAccessibility.nativeGetScrollXJNI(nativeNode));
+        event.setMaxScrollY(BrowserAccessibility.nativeGetScrollYJNI(nativeNode));
+
+        switch (eventType) {
+            case AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED:
+                event.setFromIndex(
+                        BrowserAccessibility.nativeGetTextChangeFromIndexJNI(nativeNode));
+                event.setAddedCount(
+                        BrowserAccessibility.nativeGetTextChangeAddedCountJNI(nativeNode));
+                event.setRemovedCount(
+                        BrowserAccessibility.nativeGetTextChangeRemovedCountJNI(nativeNode));
+                event.setBeforeText(
+                        BrowserAccessibility.nativeGetTextChangeBeforeTextJNI(nativeNode));
+                event.getText().add(BrowserAccessibility.nativeGetNameJNI(nativeNode));
+                break;
+            case AccessibilityEvent.TYPE_VIEW_TEXT_SELECTION_CHANGED:
+                event.setFromIndex(BrowserAccessibility.nativeGetSelectionStartJNI(nativeNode));
+                event.setToIndex(BrowserAccessibility.nativeGetSelectionEndJNI(nativeNode));
+                event.setItemCount(BrowserAccessibility.nativeGetEditableTextLengthJNI(nativeNode));
+                event.getText().add(BrowserAccessibility.nativeGetNameJNI(nativeNode));
+                break;
+            default:
+                break;
+        }
+
+        int rootId = nativeGetRootId(mNativeObj);
+        if (virtualViewId == rootId) {
+            virtualViewId = View.NO_ID;
+        }
+        event.setSource(mView, virtualViewId);
+
+        // This is currently needed if we want Android to draw the yellow box around
+        // the item that has accessibility focus. In practice, this doesn't seem to slow
+        // things down, because it's only called when the accessibility focus moves.
+        // TODO(dmazzoni): remove this if/when Android framework fixes bug.
+        mContentViewCore.getContainerView().invalidate();
+
+        mContentViewCore.getContainerView().requestSendAccessibilityEvent(mView, event);
+    }
+
+    @CalledByNative
+    private void handlePageLoaded(int id) {
+        if (mUserHasTouchExplored) return;
+
+        if (mFocusPageOnLoad) {
+            // Focus the natively focused node (usually document),
+            // if this feature is enabled.
+            mAccessibilityFocusId = id;
+            sendAccessibilityEvent(id, AccessibilityEvent.TYPE_VIEW_FOCUSED);
+        }
+    }
+
+    @CalledByNative
+    private void handleFocusChanged(int id) {
+        if (mAccessibilityFocusId == id) return;
+
+        mAccessibilityFocusId = id;
+        sendAccessibilityEvent(id, AccessibilityEvent.TYPE_VIEW_FOCUSED);
+    }
+
+    @CalledByNative
+    private void handleCheckStateChanged(int id) {
+        sendAccessibilityEvent(id, AccessibilityEvent.TYPE_VIEW_CLICKED);
+    }
+
+    @CalledByNative
+    private void handleTextSelectionChanged(int id) {
+        sendAccessibilityEvent(id, AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED);
+        sendAccessibilityEvent(id, AccessibilityEvent.TYPE_VIEW_TEXT_SELECTION_CHANGED);
+    }
+
+    @CalledByNative
+    private void handleEditableTextChanged(int id) {
+        sendAccessibilityEvent(id, AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED);
+        sendAccessibilityEvent(id, AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED);
+    }
+
+    @CalledByNative
+    private void handleContentChanged(int id) {
+        sendAccessibilityEvent(id, AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED);
+    }
+
+    @CalledByNative
+    private void handleNavigate() {
+        mAccessibilityFocusId = View.NO_ID;
+        mUserHasTouchExplored = false;
+        mFrameInfoInitialized = false;
+    }
+
+    @CalledByNative
+    private void handleScrolledToAnchor(int id) {
+        if (mAccessibilityFocusId == id) {
+            return;
+        }
+
+        mAccessibilityFocusId = id;
+        sendAccessibilityEvent(id, AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
+    }
+
+    @CalledByNative
+    private void announceObjectShow(int id, boolean forceAssertive) {
+        if (!mAccessibilityManager.isEnabled()) {
+            return;
+        }
+
+        int nativeNode = nativeGetNativeNodeById(mNativeObj, id);
+        String nodeName = BrowserAccessibility.nativeGetNameJNI(nativeNode);
+
+        // TODO(aboxhall): handle forceAssertive and other live region features
+        // once supported by framework.
+        mView.announceForAccessibility(nodeName);
+    }
+
+    private native int nativeGetRootId(int nativeBrowserAccessibilityManagerAndroid);
+    private native int nativeHitTest(int nativeBrowserAccessibilityManagerAndroid, int x, int y);
+    private native int nativeGetNativeNodeById(
+        int nativeBrowserAccessibilityManagerAndroid, int id);
+}