Add ContextMenu support upstream for Android

chrome/android/java/src/org/chromium/chrome/browser/contextmenu/ContextMenuHelper.java

+// Copyright 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.chrome.browser.contextmenu;
+
+import android.view.ContextMenu;
+import android.view.ContextMenu.ContextMenuInfo;
+import android.view.HapticFeedbackConstants;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.view.MenuItem.OnMenuItemClickListener;
+import android.view.View;
+import android.view.ViewTreeObserver;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.content.browser.ContentView;
+import org.chromium.content.browser.ContentViewCore;
+
+import android.view.View.OnCreateContextMenuListener;
+
+import com.google.common.annotations.VisibleForTesting;
+
+/**
+ * A helper class that handles generating context menus for {@link ContentView}s.
+ */
+public class ContextMenuHelper implements OnCreateContextMenuListener, OnMenuItemClickListener {
+    private long mNativeContextMenuHelper;
+
+    private ContextMenuPopulator mPopulator;
+    private ContextMenuParams mCurrentContextMenuParams;
+
+    private ContextMenuHelper(long nativeContextMenuHelper) {
+        mNativeContextMenuHelper = nativeContextMenuHelper;
+    }
+
+    @CalledByNative
+    private static ContextMenuHelper create(long nativeContextMenuHelper) {
+        return new ContextMenuHelper(nativeContextMenuHelper);
+    }
+
+    @CalledByNative
+    private void destroy() {
+        mNativeContextMenuHelper = 0;
+    }
+
+    /**
+     * @param populator A {@link ContextMenuPopulator} that is responsible for managing and showing
+     *                  context menus.
+     */
+    @CalledByNative
+    private void setPopulator(ContextMenuPopulator populator) {
+        mPopulator = populator;
+    }
+
+    /**
+     * Starts showing a context menu for {@code view} based on {@code params}.
+     * @param contentViewCore The {@link ContentViewCore} to show the menu to.
+     * @param params          The {@link ContextMenuParams} that indicate what menu items to show.
+     */
+    @CalledByNative
+    private void showContextMenu(ContentViewCore contentViewCore, ContextMenuParams params) {
+        if (!shouldShowMenu(params)) return;
+
+        mCurrentContextMenuParams = params;
+
+        View view = contentViewCore.getContainerView();
+        view.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
+        if (view instanceof ContentView) ((ContentView) view).setIgnoreRemainingTouchEvents();
+        view.setOnCreateContextMenuListener(this);
+        view.showContextMenu();
+    }
+
+    /**
+     * Starts a download based on the current {@link ContextMenuParams}.
+     * @param isLink Whether or not the download target is a link.
+     */
+    public void startContextMenuDownload(boolean isLink) {
+        if (mNativeContextMenuHelper != 0) nativeOnStartDownload(mNativeContextMenuHelper, isLink);
+    }
+
+    @Override
+    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
+        if (!shouldShowMenu(mCurrentContextMenuParams)) return;
+
+        if (mCurrentContextMenuParams.isCustomMenu()) {
+            for (int i = 0; i < mCurrentContextMenuParams.getCustomMenuSize(); i++) {
+                menu.add(Menu.NONE, i, Menu.NONE, mCurrentContextMenuParams.getCustomLabelAt(i));
+            }
+        } else {
+            assert mPopulator != null;
+            mPopulator.buildContextMenu(menu, v.getContext(), mCurrentContextMenuParams);
+        }
+
+        for (int i = 0; i < menu.size(); i++) {
+            menu.getItem(i).setOnMenuItemClickListener(this);
+        }
+    }
+
+    @Override
+    public boolean onMenuItemClick(MenuItem item) {
+        if (mCurrentContextMenuParams.isCustomMenu()) {
+            if (mNativeContextMenuHelper != 0) {
+                final int action = mCurrentContextMenuParams.getCustomActionAt(item.getItemId());
+                nativeOnCustomItemSelected(mNativeContextMenuHelper, action);
+            }
+            return true;
+        } else {
+            return mPopulator.onItemSelected(this, mCurrentContextMenuParams, item.getItemId());
+        }
+    }
+
+    /**
+     * @return The {@link ContextMenuPopulator} responsible for populating the context menu.
+     */
+    @VisibleForTesting
+    public ContextMenuPopulator getPopulator() {
+        return mPopulator;
+    }
+
+    private boolean shouldShowMenu(ContextMenuParams params) {
+        // Custom menus are handled by this class and do not require a ContextMenuPopulator.
+        return params.isCustomMenu() ||
+                (mPopulator != null && mPopulator.shouldShowContextMenu(params));
+    }
+
+    private native void nativeOnStartDownload(long nativeContextMenuHelper, boolean isLink);
+    private native void nativeOnCustomItemSelected(long nativeContextMenuHelper, int action);
+}