Merge java_staging/src into java/src.

chrome/android/java_staging/src/org/chromium/chrome/browser/webapps/ActivityAssigner.java

Index: chrome/android/java_staging/src/org/chromium/chrome/browser/webapps/ActivityAssigner.java
diff --git a/chrome/android/java_staging/src/org/chromium/chrome/browser/webapps/ActivityAssigner.java b/chrome/android/java_staging/src/org/chromium/chrome/browser/webapps/ActivityAssigner.java
deleted file mode 100644
index 30bbb8e57b8c87629feda504dacb7593a87353ef..0000000000000000000000000000000000000000
--- a/chrome/android/java_staging/src/org/chromium/chrome/browser/webapps/ActivityAssigner.java
+++ /dev/null
@@ -1,266 +0,0 @@
-// 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.webapps;
-
-import android.content.Context;
-import android.content.SharedPreferences;
-import android.util.Log;
-
-import org.chromium.base.ThreadUtils;
-import org.chromium.base.VisibleForTesting;
-
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-/**
- * Manages a rotating LRU buffer of WebappActivities to assign webapps to.
- *
- * In order to accommodate a limited number of WebappActivities with a potentially unlimited number
- * of webapps, we have to rotate the available WebappActivities between the webapps we start up.
- * Activities are reused in order of when they were last used, with the least recently used
- * ones culled first.
- *
- * It is impossible to know whether Tasks have been removed from the Recent Task list without the
- * GET_TASKS permission.  As a result, the list of Activities inside the Recent Task list will
- * be highly unlikely to match the list maintained in memory.  Instead, we store the mapping as it
- * was the last time we changed it, which allows us to launch webapps in the WebappActivity they
- * were most recently associated with in cases where a user restarts a webapp from the Recent Tasks.
- * Note that in situations where the user manually clears the app data, we will again have an
- * incorrect mapping.
- *
- * Unless otherwise noted, all methods MUST be called on the UI thread to avoid threading issues.
- *
- * EXAMPLE:
- * - 3 Activities are available for assignment (0, 1, 2).
- * - 4 webapps exist (X, Y, Z, W).
- *
- *    ACTION        EFFECT                                                ACTIVITY LIST
- * 0) Clean slate                                                         (0 -) (1 -) (2 -)
- * 1) Start X       Assigned to Activity 0 and pushed back.               (1 -) (2 -) (0 X)
- * 2) Start Y       Assigned to Activity 1 and pushed back.               (2 -) (0 X) (1 Y)
- * 3) Start Z       Assigned to Activity 2 and pushed back.               (0 X) (1 Y) (2 Z)
- * 4) Restart Y     Re-assigned to Activity 1 and pushed back.            (0 X) (2 Z) (1 Y)
- * 4) Start W       Assigned to Activity 0 and pushed back.  X evicted.   (2 Z) (1 Y) (0 W)
- * 5) Restart X     Assigned to Activity 2 and pushed back.  Z evicted.   (1 Y) (0 W) (2 X)
- */
-public class ActivityAssigner {
-    private static final String TAG = "ActivityAssigner";
-
-    // Don't ever change this.  10 is enough for everyone.
-    static final int NUM_WEBAPP_ACTIVITIES = 10;
-
-    // A sanity check limit to ensure that we aren't reading an unreasonable number of preferences.
-    // This number is different from above because the number of WebappActivities available may
-    // change.
-    static final int MAX_WEBAPP_ACTIVITIES_EVER = 100;
-
-    // Don't ever change the package.  Left for backwards compatibility.
-    @VisibleForTesting
-    static final String PREF_PACKAGE = "com.google.android.apps.chrome.webapps";
-    static final String PREF_NUM_SAVED_ENTRIES = "ActivityAssigner.numSavedEntries";
-    static final String PREF_ACTIVITY_INDEX = "ActivityAssigner.activityIndex";
-    static final String PREF_WEBAPP_ID = "ActivityAssigner.webappId";
-
-    static final int INVALID_ACTIVITY_INDEX = -1;
-
-    private static ActivityAssigner sInstance;
-
-    private final Context mContext;
-    private final List<ActivityEntry> mActivityList;
-
-    static class ActivityEntry {
-        final int mActivityIndex;
-        final String mWebappId;
-
-        ActivityEntry(int activity, String webapp) {
-            mActivityIndex = activity;
-            mWebappId = webapp;
-        }
-    }
-
-    /**
-     * Returns the singleton instance, creating it if necessary.
-     */
-    public static ActivityAssigner instance(Context context) {
-        ThreadUtils.assertOnUiThread();
-        if (sInstance == null) {
-            sInstance = new ActivityAssigner(context);
-        }
-        return sInstance;
-    }
-
-    private ActivityAssigner(Context context) {
-        mContext = context.getApplicationContext();
-        mActivityList = new ArrayList<ActivityEntry>();
-
-        restoreActivityList();
-    }
-
-    /**
-     * Assigns the webapp with the given ID to one of the available WebappActivities.
-     * If we know that the webapp was previously launched in one of the Activities, re-use it.
-     * Otherwise, take the least recently used WebappActivity ID and use that.
-     * @param webappId ID of the webapp.
-     * @return Index of the Activity to use for the webapp.
-     */
-    int assign(String webappId) {
-        // Reuse a running Activity with the same ID, if it exists.
-        int activityIndex = checkIfAssigned(webappId);
-
-        // Allocate the one in the front of the list.
-        if (activityIndex == INVALID_ACTIVITY_INDEX) {
-            activityIndex = mActivityList.get(0).mActivityIndex;
-            ActivityEntry newEntry = new ActivityEntry(activityIndex, webappId);
-            mActivityList.set(0, newEntry);
-        }
-
-        markActivityUsed(activityIndex, webappId);
-        return activityIndex;
-    }
-
-    /**
-     * Checks if the webapp with the given ID has been assigned to an Activity already.
-     * @param webappId ID of the webapp being displayed.
-     * @return Index of the Activity for the webapp if assigned, INVALID_ACTIVITY_INDEX otherwise.
-     */
-    int checkIfAssigned(String webappId) {
-        if (webappId == null) {
-            return INVALID_ACTIVITY_INDEX;
-        }
-
-        // Go backwards in the queue to catch more recent instances of any duplicated webapps.
-        for (int i = mActivityList.size() - 1; i >= 0; i--) {
-            if (webappId.equals(mActivityList.get(i).mWebappId)) {
-                return mActivityList.get(i).mActivityIndex;
-            }
-        }
-        return INVALID_ACTIVITY_INDEX;
-    }
-
-    /**
-     * Moves a WebappActivity to the back of the queue, indicating that the Webapp is still in use
-     * and shouldn't be killed.
-     * @param activityIndex Index of the WebappActivity.
-     * @param webappId ID of the webapp being shown in the WebappActivity.
-     */
-    void markActivityUsed(int activityIndex, String webappId) {
-        // Find the entry corresponding to the Activity.
-        int elementIndex = findActivityElement(activityIndex);
-
-        if (elementIndex == -1) {
-            Log.e(TAG, "Failed to find WebappActivity entry: " + activityIndex + ", " + webappId);
-            return;
-        }
-
-        // We have to reassign the webapp ID in case WebappActivities get repurposed.
-        ActivityEntry updatedEntry = new ActivityEntry(activityIndex, webappId);
-        mActivityList.remove(elementIndex);
-        mActivityList.add(updatedEntry);
-        storeActivityList();
-    }
-
-    /**
-     * Finds the index of the ActivityElement corresponding to the given activityIndex.
-     * @param activityIndex Index of the activity to find.
-     * @return The index of the ActivityElement in the activity list, or -1 if it couldn't be found.
-     */
-    private int findActivityElement(int activityIndex) {
-        for (int elementIndex = 0; elementIndex < mActivityList.size(); elementIndex++) {
-            if (mActivityList.get(elementIndex).mActivityIndex == activityIndex) {
-                return elementIndex;
-            }
-        }
-        return -1;
-    }
-
-    /**
-     * Returns the current mapping between Activities and webapps.
-     */
-    @VisibleForTesting
-    List<ActivityEntry> getEntries() {
-        return mActivityList;
-    }
-
-    /**
-     * Restores/creates the mapping between webapps and WebappActivities.
-     * The logic is slightly complicated to future-proof against situations where the number of
-     * WebappActivities is changed.
-     */
-    private void restoreActivityList() {
-        boolean isMapDirty = false;
-        mActivityList.clear();
-
-        // Create a Set of indices corresponding to every possible Activity.
-        // As ActivityEntries are read, they are and removed from this list to indicate that the
-        // Activity has already been assigned.
-        Set<Integer> availableWebapps = new HashSet<Integer>();
-        for (int i = 0; i < NUM_WEBAPP_ACTIVITIES; ++i) {
-            availableWebapps.add(i);
-        }
-
-        // Restore any entries that were previously saved.  If it seems that the preferences have
-        // been corrupted somehow, just discard the whole map.
-        SharedPreferences prefs = mContext.getSharedPreferences(PREF_PACKAGE, Context.MODE_PRIVATE);
-        try {
-            final int numSavedEntries = prefs.getInt(PREF_NUM_SAVED_ENTRIES, 0);
-            if (numSavedEntries <= NUM_WEBAPP_ACTIVITIES) {
-                for (int i = 0; i < numSavedEntries; ++i) {
-                    String currentActivityIndexPref = PREF_ACTIVITY_INDEX + i;
-                    String currentWebappIdPref = PREF_WEBAPP_ID + i;
-
-                    int activityIndex = prefs.getInt(currentActivityIndexPref, i);
-                    String webappId = prefs.getString(currentWebappIdPref, null);
-                    ActivityEntry entry = new ActivityEntry(activityIndex, webappId);
-
-                    if (availableWebapps.remove(entry.mActivityIndex)) {
-                        mActivityList.add(entry);
-                    } else {
-                        // If the same activity was assigned to two different entries, or if the
-                        // number of activities changed, discard it and mark that it needs to be
-                        // rewritten.
-                        isMapDirty = true;
-                    }
-                }
-            }
-        } catch (ClassCastException exception) {
-            // Something went wrong reading the preferences.  Nuke everything.
-            mActivityList.clear();
-            availableWebapps.clear();
-            for (int i = 0; i < NUM_WEBAPP_ACTIVITIES; ++i) {
-                availableWebapps.add(i);
-            }
-        }
-
-        // Add entries for any missing WebappActivities.
-        for (Integer availableIndex : availableWebapps) {
-            ActivityEntry entry = new ActivityEntry(availableIndex, null);
-            mActivityList.add(entry);
-            isMapDirty = true;
-        }
-
-        if (isMapDirty) {
-            storeActivityList();
-        }
-    }
-
-    /**
-     * Saves the mapping between webapps and WebappActivities.
-     */
-    private void storeActivityList() {
-        SharedPreferences prefs = mContext.getSharedPreferences(PREF_PACKAGE, Context.MODE_PRIVATE);
-        SharedPreferences.Editor editor = prefs.edit();
-        editor.clear();
-        editor.putInt(PREF_NUM_SAVED_ENTRIES, mActivityList.size());
-        for (int i = 0; i < mActivityList.size(); ++i) {
-            String currentActivityIndexPref = PREF_ACTIVITY_INDEX + i;
-            String currentWebappIdPref = PREF_WEBAPP_ID + i;
-            editor.putInt(currentActivityIndexPref, mActivityList.get(i).mActivityIndex);
-            editor.putString(currentWebappIdPref, mActivityList.get(i).mWebappId);
-        }
-        editor.apply();
-    }
-}