Revert of Add tab persistence support for CustomTabs.

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabTabPersistencePolicy.java

Index: chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabTabPersistencePolicy.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabTabPersistencePolicy.java b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabTabPersistencePolicy.java
deleted file mode 100644
index f3ea43ad3acffa0dd3f6ac86e56f9347f28aee8f..0000000000000000000000000000000000000000
--- a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabTabPersistencePolicy.java
+++ /dev/null
@@ -1,387 +0,0 @@
-// 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.customtabs;
-
-import android.app.Activity;
-import android.os.AsyncTask;
-import android.os.StrictMode;
-import android.util.Pair;
-import android.util.SparseBooleanArray;
-
-import org.chromium.base.ApiCompatibilityUtils;
-import org.chromium.base.ApplicationStatus;
-import org.chromium.base.Callback;
-import org.chromium.base.Log;
-import org.chromium.base.StreamUtil;
-import org.chromium.base.ThreadUtils;
-import org.chromium.chrome.browser.TabState;
-import org.chromium.chrome.browser.compositor.layouts.content.TabContentManager;
-import org.chromium.chrome.browser.tabmodel.TabModel;
-import org.chromium.chrome.browser.tabmodel.TabModelSelector;
-import org.chromium.chrome.browser.tabmodel.TabPersistencePolicy;
-import org.chromium.chrome.browser.tabmodel.TabPersistentStore;
-
-import java.io.BufferedInputStream;
-import java.io.DataInputStream;
-import java.io.File;
-import java.io.FileInputStream;
-import java.lang.ref.WeakReference;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Executor;
-
-import javax.annotation.Nullable;
-
-/**
- * Handles the Custom Tab specific behaviors of tab persistence.
- */
-public class CustomTabTabPersistencePolicy implements TabPersistencePolicy {
-
-    static final String SAVED_STATE_DIRECTORY = "custom_tabs";
-
-    /** Threshold where old state files should be deleted (30 days). */
-    protected static final long STATE_EXPIRY_THRESHOLD = 30L * 24 * 60 * 60 * 1000;
-
-    /** Maximum number of state files before we should start deleting old ones. */
-    protected static final int MAXIMUM_STATE_FILES = 30;
-
-    private static final String TAG = "tabmodel";
-
-    /** Prevents two state directories from getting created simultaneously. */
-    private static final Object DIR_CREATION_LOCK = new Object();
-
-    /**
-     * Prevents two clean up tasks from getting created simultaneously. Also protects against
-     * incorrectly interleaving create/run/cancel on the task.
-     */
-    private static final Object CLEAN_UP_TASK_LOCK = new Object();
-
-    private static File sStateDirectory;
-    private static AsyncTask<Void, Void, Void> sCleanupTask;
-
-    /**
-     * The folder where the state should be saved to.
-     * @return A file representing the directory that contains TabModelSelector states.
-     */
-    public static File getOrCreateCustomTabModeStateDirectory() {
-        synchronized (DIR_CREATION_LOCK) {
-            if (sStateDirectory == null) {
-                sStateDirectory = new File(
-                        TabPersistentStore.getOrCreateBaseStateDirectory(), SAVED_STATE_DIRECTORY);
-                StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();
-                StrictMode.allowThreadDiskWrites();
-                try {
-                    if (!sStateDirectory.exists() && !sStateDirectory.mkdirs()) {
-                        Log.e(TAG, "Failed to create state folder: " + sStateDirectory);
-                    }
-                } finally {
-                    StrictMode.setThreadPolicy(oldPolicy);
-                }
-            }
-        }
-        return sStateDirectory;
-    }
-
-    private final int mTaskId;
-    private final boolean mShouldRestore;
-
-    private AsyncTask<Void, Void, Void> mInitializationTask;
-    private boolean mDestroyed;
-
-    /**
-     * Constructs a persistence policy for a given Custom Tab.
-     *
-     * @param taskId The task ID that the owning Custom Tab is in.
-     * @param shouldRestore Whether an attempt to restore tab state information should be done on
-     *                      startup.
-     */
-    public CustomTabTabPersistencePolicy(int taskId, boolean shouldRestore) {
-        mTaskId = taskId;
-        mShouldRestore = shouldRestore;
-    }
-
-    @Override
-    public File getOrCreateStateDirectory() {
-        return getOrCreateCustomTabModeStateDirectory();
-    }
-
-    @Override
-    public String getStateFileName() {
-        return TabPersistentStore.getStateFileName(Integer.toString(mTaskId));
-    }
-
-    @Override
-    @Nullable
-    public String getStateToBeMergedFileName() {
-        return null;
-    }
-
-    @Override
-    public boolean performInitialization(Executor executor) {
-        mInitializationTask = new AsyncTask<Void, Void, Void>() {
-            @Override
-            protected Void doInBackground(Void... params) {
-                File stateDir = getOrCreateStateDirectory();
-                File metadataFile = new File(stateDir, getStateFileName());
-                if (metadataFile.exists()) {
-                    if (mShouldRestore) {
-                        if (!metadataFile.setLastModified(System.currentTimeMillis())) {
-                            Log.e(TAG, "Unable to update last modified time: " + metadataFile);
-                        }
-                    } else {
-                        if (!metadataFile.delete()) {
-                            Log.e(TAG, "Failed to delete file: " + metadataFile);
-                        }
-                    }
-                }
-                return null;
-            }
-        }.executeOnExecutor(executor);
-
-        return true;
-    }
-
-    @Override
-    public void waitForInitializationToFinish() {
-        if (mInitializationTask == null) return;
-        try {
-            mInitializationTask.get();
-        } catch (InterruptedException | ExecutionException e) {
-            // Ignore and proceed.
-        }
-    }
-
-    @Override
-    public boolean isMergeInProgress() {
-        return false;
-    }
-
-    @Override
-    public void setMergeInProgress(boolean isStarted) {
-        assert false : "Merge not supported in Custom Tabs";
-    }
-
-    @Override
-    public void cancelCleanupInProgress() {
-        synchronized (CLEAN_UP_TASK_LOCK) {
-            if (sCleanupTask != null) sCleanupTask.cancel(true);
-        }
-    }
-
-    @Override
-    public void cleanupUnusedFiles(Callback<List<String>> filesToDelete) {
-        synchronized (CLEAN_UP_TASK_LOCK) {
-            if (sCleanupTask != null) sCleanupTask.cancel(true);
-            sCleanupTask = new CleanUpTabStateDataTask(filesToDelete);
-            sCleanupTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
-        }
-    }
-
-    @Override
-    public void setTabContentManager(TabContentManager cache) {
-    }
-
-    @Override
-    public void destroy() {
-        mDestroyed = true;
-    }
-
-    /**
-     * Given a list of metadata files, determine which are applicable for deletion based on the
-     * deletion strategy of Custom Tabs.
-     *
-     * @param currentTimeMillis The current time in milliseconds
-     *                          ({@link System#currentTimeMillis()}.
-     * @param allMetadataFiles The complete list of all metadata files to check.
-     * @return The list of metadata files that are applicable for deletion.
-     */
-    protected static List<File> getMetadataFilesForDeletion(
-            long currentTimeMillis, List<File> allMetadataFiles) {
-        Collections.sort(allMetadataFiles, new Comparator<File>() {
-            @Override
-            public int compare(File lhs, File rhs) {
-                long lhsModifiedTime = lhs.lastModified();
-                long rhsModifiedTime = rhs.lastModified();
-
-                // Sort such that older files (those with an lower timestamp number) are at the
-                // end of the sorted listed.
-                return ApiCompatibilityUtils.compareLong(rhsModifiedTime, lhsModifiedTime);
-            }
-        });
-
-        List<File> stateFilesApplicableForDeletion = new ArrayList<File>();
-        for (int i = 0; i < allMetadataFiles.size(); i++) {
-            File file = allMetadataFiles.get(i);
-            long fileAge = currentTimeMillis - file.lastModified();
-            if (i >= MAXIMUM_STATE_FILES || fileAge >= STATE_EXPIRY_THRESHOLD) {
-                stateFilesApplicableForDeletion.add(file);
-            }
-        }
-        return stateFilesApplicableForDeletion;
-    }
-
-    /**
-     * Get all current Tab IDs used by the specified activity.
-     *
-     * @param activity The activity whose tab IDs are to be collected from.
-     * @param tabIds Where the tab IDs should be added to.
-     */
-    private static void getAllTabIdsForActivity(CustomTabActivity activity, Set<Integer> tabIds) {
-        if (activity == null) return;
-        TabModelSelector selector = activity.getTabModelSelector();
-        if (selector == null) return;
-        List<TabModel> models = selector.getModels();
-        for (int i = 0; i < models.size(); i++) {
-            TabModel model = models.get(i);
-            for (int j = 0; j < model.getCount(); j++) {
-                tabIds.add(model.getTabAt(j).getId());
-            }
-        }
-    }
-
-    /**
-     * Gathers all of the tab IDs and task IDs for all currently live Custom Tabs.
-     *
-     * @param liveTabIds Where tab IDs will be added.
-     * @param liveTaskIds Where task IDs will be added.
-     */
-    protected static void getAllLiveTabAndTaskIds(
-            Set<Integer> liveTabIds, Set<Integer> liveTaskIds) {
-        ThreadUtils.assertOnUiThread();
-
-        List<WeakReference<Activity>> activities = ApplicationStatus.getRunningActivities();
-        for (int i = 0; i < activities.size(); i++) {
-            Activity activity = activities.get(i).get();
-            if (activity == null) continue;
-            if (!(activity instanceof CustomTabActivity)) continue;
-            getAllTabIdsForActivity((CustomTabActivity) activity, liveTabIds);
-            liveTaskIds.add(activity.getTaskId());
-        }
-    }
-
-    private class CleanUpTabStateDataTask extends AsyncTask<Void, Void, Void> {
-        private final Callback<List<String>> mFilesToDeleteCallback;
-
-        private Set<Integer> mUnreferencedTabIds;
-        private List<File> mDeletableMetadataFiles;
-        private Map<File, SparseBooleanArray> mTabIdsByMetadataFile;
-
-        CleanUpTabStateDataTask(Callback<List<String>> filesToDelete) {
-            mFilesToDeleteCallback = filesToDelete;
-        }
-
-        @Override
-        protected Void doInBackground(Void... voids) {
-            if (mDestroyed) return null;
-
-            mTabIdsByMetadataFile = new HashMap<>();
-            mUnreferencedTabIds = new HashSet<>();
-
-            File[] stateFiles = getOrCreateStateDirectory().listFiles();
-            if (stateFiles == null) return null;
-
-            Set<Integer> allTabIds = new HashSet<>();
-            Set<Integer> allReferencedTabIds = new HashSet<>();
-            List<File> metadataFiles = new ArrayList<>();
-            for (File file : stateFiles) {
-                if (TabPersistentStore.isStateFile(file.getName())) {
-                    metadataFiles.add(file);
-
-                    SparseBooleanArray tabIds = new SparseBooleanArray();
-                    mTabIdsByMetadataFile.put(file, tabIds);
-                    getTabsFromStateFile(tabIds, file);
-                    for (int i = 0; i < tabIds.size(); i++) {
-                        allReferencedTabIds.add(tabIds.keyAt(i));
-                    }
-                    continue;
-                }
-
-                Pair<Integer, Boolean> tabInfo = TabState.parseInfoFromFilename(file.getName());
-                if (tabInfo == null) continue;
-                allTabIds.add(tabInfo.first);
-            }
-
-            mUnreferencedTabIds.addAll(allTabIds);
-            mUnreferencedTabIds.removeAll(allReferencedTabIds);
-
-            mDeletableMetadataFiles = getMetadataFilesForDeletion(
-                    System.currentTimeMillis(), metadataFiles);
-            return null;
-        }
-
-        @Override
-        protected void onPostExecute(Void unused) {
-            List<String> filesToDelete = new ArrayList<>();
-            if (mDestroyed) {
-                mFilesToDeleteCallback.onResult(filesToDelete);
-                return;
-            }
-
-            if (mUnreferencedTabIds.isEmpty() && mDeletableMetadataFiles.isEmpty()) {
-                mFilesToDeleteCallback.onResult(filesToDelete);
-                return;
-            }
-
-            Set<Integer> liveTabIds = new HashSet<>();
-            Set<Integer> liveTaskIds = new HashSet<>();
-            getAllLiveTabAndTaskIds(liveTabIds, liveTaskIds);
-
-            for (Integer unreferencedTabId : mUnreferencedTabIds) {
-                // Ignore tabs that are referenced by live activities as they might not have been
-                // able to write out their state yet.
-                if (liveTabIds.contains(unreferencedTabId)) continue;
-
-                // The tab state is not referenced by any current activities or any metadata files,
-                // so mark it for deletion.
-                filesToDelete.add(TabState.getTabStateFilename(unreferencedTabId, false));
-            }
-
-            for (int i = 0; i < mDeletableMetadataFiles.size(); i++) {
-                File metadataFile = mDeletableMetadataFiles.get(i);
-                String id = TabPersistentStore.getStateFileUniqueId(metadataFile.getName());
-                try {
-                    int taskId = Integer.parseInt(id);
-
-                    // Ignore the metadata file if it belongs to a currently live CustomTabActivity.
-                    if (liveTaskIds.contains(taskId)) continue;
-
-                    filesToDelete.add(metadataFile.getName());
-
-                    SparseBooleanArray unusedTabIds = mTabIdsByMetadataFile.get(metadataFile);
-                    if (unusedTabIds == null) continue;
-                    for (int j = 0; j < unusedTabIds.size(); j++) {
-                        filesToDelete.add(TabState.getTabStateFilename(
-                                unusedTabIds.keyAt(j), false));
-                    }
-                } catch (NumberFormatException ex) {
-                    assert false : "Unexpected tab metadata file found: " + metadataFile.getName();
-                    continue;
-                }
-            }
-
-            mFilesToDeleteCallback.onResult(filesToDelete);
-        }
-
-        private void getTabsFromStateFile(SparseBooleanArray tabIds, File metadataFile) {
-            DataInputStream stream = null;
-            try {
-                stream = new DataInputStream(
-                        new BufferedInputStream(new FileInputStream(metadataFile)));
-                TabPersistentStore.readSavedStateFile(stream, null, tabIds, false);
-            } catch (Exception e) {
-                Log.e(TAG, "Unable to read state for " + metadataFile.getName() + ": " + e);
-            } finally {
-                StreamUtil.closeQuietly(stream);
-            }
-        }
-    }
-}