Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/toolbar/KeyboardNavigationListener.java

+// Copyright 2015 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.chrome.browser.toolbar;
+
+import android.view.KeyEvent;
+import android.view.View;
+import android.view.View.OnKeyListener;
+
+/**
+ * This is an abstract class to override keyboard navigation behavior for views.
+ */
+abstract class KeyboardNavigationListener implements OnKeyListener {
+
+    public KeyboardNavigationListener() {
+        super();
+    }
+
+    @Override
+    public boolean onKey(View v, int keyCode, KeyEvent event) {
+        if (keyCode == KeyEvent.KEYCODE_TAB && event.getAction() == KeyEvent.ACTION_DOWN) {
+            if (event.hasNoModifiers()) {
+                View forward = getNextFocusForward();
+                if (forward != null) return forward.requestFocus();
+            } else if (event.isShiftPressed()) {
+                View backward = getNextFocusBackward();
+                if (backward != null) return backward.requestFocus();
+            }
+        } else if (keyCode == KeyEvent.KEYCODE_ENTER && event.getAction() == KeyEvent.ACTION_UP) {
+            return handleEnterKeyPress();
+        }
+        return false;
+    }
+
+    /**
+     * Get the view to be focused on a TAB click. If you return null, the default key event
+     * processing will occur instead of attempting to focus.
+     * @return The view to gain focus.
+     */
+    public View getNextFocusForward() {
+        return null;
+    }
+
+    /**
+     * Get the view to be focused on a Shift + TAB click. If you return null, the default key event
+     * processing will occur instead of attempting to focus.
+     * @return The view to gain focus.
+     */
+    public View getNextFocusBackward() {
+        return null;
+    }
+
+    /**
+     * Allows the extending class to special case the enter key press handling.
+     * @return Whether the enter key was handled
+     */
+    protected boolean handleEnterKeyPress() {
+        return false;
+    }
+}