Fix races in ConfirmPassword/Pattern

- Add a CheckLockResultTracker to track result of async lock check so that
  it can finish on configuration change;
- Let the pending lock check finish and ignore subsequent check requests;
- Add a mDisappearing flag to prevent running disappear animation
  multiple times;
- Check whether activity is still active after disappear animation
  before setting result and finishing it;
- Remove no longer used mNumWrongConfirmAttempts;

Bug:23190499
Change-Id: If1784d3d1fcc152ac06137b12748b9def5726692

src/com/android/settings/CredentialCheckResultTracker.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings;
+
+import android.app.Fragment;
+import android.content.Intent;
+import android.os.Bundle;
+
+/**
+ * An invisible retained fragment to track lock check result.
+ */
+class CredentialCheckResultTracker extends Fragment {
+
+    private Listener mListener;
+    private boolean mHasResult = false;
+
+    private boolean mResultMatched;
+    private Intent mResultData;
+    private int mResultTimeoutMs;
+    private int mResultEffectiveUserId;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setRetainInstance(true);
+    }
+
+    public void setListener(Listener listener) {
+        if (mListener == listener) {
+            return;
+        }
+
+        mListener = listener;
+        if (mListener != null && mHasResult) {
+            mListener.onCredentialChecked(mResultMatched, mResultData, mResultTimeoutMs,
+                    mResultEffectiveUserId);
+        }
+    }
+
+    public void setResult(boolean matched, Intent intent, int timeoutMs, int effectiveUserId) {
+        mResultMatched = matched;
+        mResultData = intent;
+        mResultTimeoutMs = timeoutMs;
+        mResultEffectiveUserId = effectiveUserId;
+
+        mHasResult = true;
+        if (mListener != null) {
+            mListener.onCredentialChecked(mResultMatched, mResultData, mResultTimeoutMs,
+                    mResultEffectiveUserId);
+        }
+    }
+
+    public void clearResult() {
+        mHasResult = false;
+        mResultMatched = false;
+        mResultData = null;
+        mResultTimeoutMs = 0;
+        mResultEffectiveUserId = 0;
+    }
+
+    interface Listener {
+        public void onCredentialChecked(boolean matched, Intent intent, int timeoutMs,
+                int effectiveUserId);
+    }
+}