[Document mode] Allow multiple popup windows to appear.

chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/AsyncDocumentLauncher.java

Index: chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/AsyncDocumentLauncher.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/AsyncDocumentLauncher.java b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/AsyncDocumentLauncher.java
new file mode 100644
index 0000000000000000000000000000000000000000..98d7a188917678ca8837c74b63b43ccdfbb118a6
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/AsyncDocumentLauncher.java
@@ -0,0 +1,112 @@
+// 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.tabmodel.document;
+
+import android.app.Activity;
+import android.os.Handler;
+import android.os.SystemClock;
+
+import org.chromium.base.ThreadUtils;
+import org.chromium.chrome.browser.Tab;
+import org.chromium.chrome.browser.document.ChromeLauncherActivity;
+import org.chromium.chrome.browser.document.DocumentActivity;
+import org.chromium.chrome.browser.document.IncognitoDocumentActivity;
+import org.chromium.chrome.browser.tabmodel.document.DocumentTabModel.Entry;
+
+import java.util.ArrayList;
+
+/**
+ * Fires an Intent to launch a new DocumentActivity.  Waits for the ActivityManager to acknowledge
+ * that our task exists before firing the next Intent.
+ */
+public class AsyncDocumentLauncher {
+    /**
+     * Milliseconds to wait for Android to acknowledge that our Activity's task exists.
+     * This value is empirically defined because Android doesn't let us know when it finishes
+     * animating Activities, nor does it let us Observe the ActivityManager for when our task
+     * exists (crbug.com/498920).
+     */
+    private static final int MAX_WAIT_MS = 3000;
+
+    /** Milliseconds to wait between polls of the ActivityManager. */
+    private static final int POLLING_DELAY_MS = 100;
+
+    private class LaunchRunnable implements Runnable {
+        private final int mParentId;
+        private final AsyncTabCreationParams mAsyncParams;
+        private int mLaunchedId;
+        private long mLaunchTimestamp;
+
+        public LaunchRunnable(int parentId, AsyncTabCreationParams asyncParams) {
+            mParentId = parentId;
+            mAsyncParams = asyncParams;
+            mLaunchedId = Tab.INVALID_TAB_ID;
+        }
+
+        /** Starts an Activity to with the stored parameters. */
+        public void launch() {
+            final Activity parentActivity = ActivityDelegate.getActivityForTabId(mParentId);
+            mLaunchedId = ChromeLauncherActivity.launchDocumentInstance(
+                    parentActivity, mIsIncognito, mAsyncParams);
+            mLaunchTimestamp = SystemClock.elapsedRealtime();
+            run();
+        }
+
+        @Override
+        public void run() {
+            // Check if the Activity was already launched.
+            for (Entry task : mActivityDelegate.getTasksFromRecents(mIsIncognito)) {
+                if (task.tabId == mLaunchedId) {
+                    finishLaunch();
+                    return;
+                }
+            }
+
+            if (SystemClock.elapsedRealtime() - mLaunchTimestamp > MAX_WAIT_MS) {
+                // Check if the launch is taking excessively long.  This will likely make the
+                // previous tab disappear, but it's better than making the user wait.
+                finishLaunch();
+            } else {
+                // Wait a bit longer.
+                mHandler.postDelayed(this, POLLING_DELAY_MS);
+            }
+        }
+
+        /** Start up the next tab. */
+        private void finishLaunch() {
+            mCurrentRunnable = null;
+            if (mQueue.size() != 0) {
+                mCurrentRunnable = mQueue.remove(0);
+                mCurrentRunnable.launch();
+            }
+        }
+    }
+
+    private final boolean mIsIncognito;
+    private final Handler mHandler;
+    private final ActivityDelegate mActivityDelegate;
+    private final ArrayList<LaunchRunnable> mQueue;
+    private LaunchRunnable mCurrentRunnable;
+
+    public AsyncDocumentLauncher(boolean incognito) {
+        mIsIncognito = incognito;
+        mHandler = new Handler();
+        mActivityDelegate = new ActivityDelegate(
+                DocumentActivity.class, IncognitoDocumentActivity.class);
+        mQueue = new ArrayList<LaunchRunnable>();
+    }
+
+    /** Enqueues a tab to be launched asynchronously. */
+    public void enqueueLaunch(int parentId, AsyncTabCreationParams asyncParams) {
+        ThreadUtils.assertOnUiThread();
+        LaunchRunnable runnable = new LaunchRunnable(parentId, asyncParams);
+        if (mCurrentRunnable == null) {
+            mCurrentRunnable = runnable;
+            mCurrentRunnable.launch();
+        } else {
+            mQueue.add(runnable);
+        }
+    }
+}