Pass user gesture bit when chrome handles an intent fired by itself

chrome/android/java/src/org/chromium/chrome/browser/externalnav/IntentWithGesturesHandler.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.externalnav;
+
+import android.content.Intent;
+
+import org.chromium.chrome.browser.IntentHandler;
+import org.chromium.chrome.browser.util.IntentUtils;
+
+import java.security.SecureRandom;
+import java.util.Arrays;
+
+/**
+ * This class hold a token for the most recent launched external intent that has
+ * user gesture. If the external intent resolves to chrome itself, the user
+ * gesture will be applied to the new url request. Since there could be at most
+ * one intent chooser at a time, this class only stores the most recent intent
+ * that has user gesture. A previously launched intent with user gesture will
+ * have its token invalidated if a new one comes.
+ */
+public class IntentWithGesturesHandler {
+    /**
+     * Extra to record whether the intent is launched by user gesture.
+     */
+    public static final String EXTRA_USER_GESTURE_TOKEN =
+            "org.chromium.chrome.browser.user_gesture_token";
+
+    private static final Object INSTANCE_LOCK = new Object();
+    private static IntentWithGesturesHandler sIntentWithGesturesHandler;
+    private SecureRandom mSecureRandom;
+    private byte[] mIntentToken;
+    private String mUri;
+
+    /**
+     * Get the singleton instance of this object.
+     */
+    public static IntentWithGesturesHandler getInstance() {
+        synchronized (INSTANCE_LOCK) {
+            if (sIntentWithGesturesHandler == null) {
+                sIntentWithGesturesHandler = new IntentWithGesturesHandler();
+            }
+        }
+        return sIntentWithGesturesHandler;
+    }
+
+    private IntentWithGesturesHandler() {
+        mSecureRandom = new SecureRandom();
+    }
+
+    /**
+     * Generate a new token for the intent that has user gesture. This will
+     * invalidate the token on the previously launched intent with user gesture.
+     *
+     * @param intent Intent with user gesture.
+     */
+    public void onNewIntentWithGesture(Intent intent) {
+        mIntentToken = new byte[32];
+        mSecureRandom.nextBytes(mIntentToken);
+        intent.putExtra(EXTRA_USER_GESTURE_TOKEN, mIntentToken);
+        mUri = IntentHandler.getUrlFromIntent(intent);
+    }
+
+    /**
+     * Get the user gesture from the intent and clear the stored token.
+     *
+     * @param intent Intent that is used to launch chrome.
+     * @return true if the intent has user gesture, or false otherwise.
+     */
+    public boolean getUserGestureAndClear(Intent intent) {
+        if (mIntentToken == null || mUri == null) return false;
+        byte[] bytes = IntentUtils.safeGetByteArrayExtra(intent, EXTRA_USER_GESTURE_TOKEN);
+        boolean ret = (bytes != null) && Arrays.equals(bytes, mIntentToken)
+                && mUri.equals(IntentHandler.getUrlFromIntent(intent));
+        clear();
+        return ret;
+    }
+
+    /**
+     * Clear the gesture token.
+     */
+    public void clear() {
+        mIntentToken = null;
+        mUri = null;
+    }
+}