Allow deferred intent when the screen is locked

chrome/android/java/src/org/chromium/chrome/browser/DelayedScreenLockIntentHandler.java

Index: chrome/android/java/src/org/chromium/chrome/browser/DelayedScreenLockIntentHandler.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/DelayedScreenLockIntentHandler.java b/chrome/android/java/src/org/chromium/chrome/browser/DelayedScreenLockIntentHandler.java
new file mode 100644
index 0000000000000000000000000000000000000000..374676648702659956b606ffe1d4add197350293
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/DelayedScreenLockIntentHandler.java
@@ -0,0 +1,96 @@
+// Copyright 2016 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;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.Handler;
+import android.os.SystemClock;
+
+import org.chromium.base.ContextUtils;
+
+/**
+ * Intent handler that is specific for the situation when the screen is unlocked from pin, pattern,
+ * or password.
+ * This class handles exactly one intent unlock + dispatch at a time. It could be reused by calling
+ * updateDeferredIntent with a new intent.
+ */
+public class DelayedScreenLockIntentHandler extends BroadcastReceiver {
+    private static final int VALID_DEFERRED_PERIOD_MS = 10000;
+
+    private final Handler mTaskHandler;
+    private final Runnable mUnregisterTask;
+
+    private Intent mDeferredIntent;
+    private long mDeferredIntentCreatedTime;
+    private boolean mReceiverRegistered;
+
+    public DelayedScreenLockIntentHandler() {
+        mTaskHandler = new Handler();
+        mUnregisterTask = new Runnable() {
+            @Override
+            public void run() {
+                updateDeferredIntent(null);
+            }
+        };
+    }
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        assert Intent.ACTION_USER_PRESENT.equals(intent.getAction());
+
+        if (Intent.ACTION_USER_PRESENT.equals(intent.getAction()) && mDeferredIntent != null) {
+            context.startActivity(mDeferredIntent);
+            // Prevent the broadcast receiver from firing intent unexpectedly.
+            updateDeferredIntent(null);
+        }
+    }
+
+    /**
+     * Update the deferred intent with the target intent, also reset the deferred intent's lifecycle
+     * @param intent Target intent
+     */
+    public void updateDeferredIntent(final Intent intent) {
+        mTaskHandler.removeCallbacks(mUnregisterTask);
+
+        if (intent == null) {
+            unregisterReceiver();
+            mDeferredIntent = null;
+            return;
+        }
+
+        mDeferredIntent = intent;
+        mDeferredIntentCreatedTime = SystemClock.elapsedRealtime();
+        registerReceiver();
+        mTaskHandler.postDelayed(mUnregisterTask, VALID_DEFERRED_PERIOD_MS);
+    }
+
+    /**
+     * Register to receive ACTION_USER_PRESENT when the screen is unlocked.
+     * The ACTION_USER_PRESENT is sent by platform to indicates when user is present.
+     */
+    private void registerReceiver() {
+        if (mReceiverRegistered) return;
+
+        ContextUtils.getApplicationContext()
+                .registerReceiver(this, new IntentFilter(Intent.ACTION_USER_PRESENT));
+        mReceiverRegistered = true;
+    }
+
+    /**
+     * Unregister the receiver in one of the following situations
+     * - When the deferred intent expires
+     * - When updateDeferredIntent(null) called
+     * - When the deferred intent has been fired
+     */
+    private void unregisterReceiver() {
+        if (!mReceiverRegistered) return;
+
+        ContextUtils.getApplicationContext().unregisterReceiver(this);
+        mReceiverRegistered = false;
+    }
+}