Persistent frozen tabs

 On Tablet WebViews for frozen tabs are created on demand
 On Phone WebViews for frozen tabs are tied to the lifecycle
 of the SnapshotTab for nav screen reasons (for now)

Change-Id: I80cb48e748c4dd4b8564426d5e05b92f3eea7a36

6 files changed, 367 insertions, 154 deletions

diff --git a/src/com/android/browser/Controller.java b/src/com/android/browser/Controller.java
index efd9012..faee0c7 100644
--- a/src/com/android/browser/Controller.java
+++ b/src/com/android/browser/Controller.java
@@ -23,6 +23,7 @@ import android.content.ClipboardManager;
 import android.content.ContentProvider;
 import android.content.ContentProviderClient;
 import android.content.ContentResolver;
+import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.Context;
 import android.content.Intent;
@@ -78,6 +79,7 @@ import android.widget.Toast;
 import com.android.browser.IntentHandler.UrlData;
 import com.android.browser.UI.DropdownChangeListener;
 import com.android.browser.provider.BrowserProvider;
+import com.android.browser.provider.BrowserProvider2.Snapshots;
 import com.android.browser.search.SearchEngine;
 import com.android.common.Search;
 
@@ -326,6 +328,8 @@ public class Controller
                     webView.setInitialScale(scale);
                 }
             }
+            mTabControl.loadSnapshotTabs();
+            mUi.updateTabs(mTabControl.getTabs());
         } else {
             mTabControl.restoreState(icicle, currentTabId, restoreIncognitoTabs,
                     mUi.needsRestoreAllTabs());
@@ -797,7 +801,8 @@ public class Controller
     public void onPageFinished(Tab tab) {
         mUi.onTabDataChanged(tab);
         if (!tab.isPrivateBrowsingEnabled()
-                && !TextUtils.isEmpty(tab.getUrl())) {
+                && !TextUtils.isEmpty(tab.getUrl())
+                && !tab.isSnapshot()) {
             if (tab.inForeground() && !didUserStopLoading()
                     || !tab.inForeground()) {
                 // Only update the bookmark screenshot if the user did not
@@ -1605,19 +1610,28 @@ public class Controller
                 // TODO: Show error messages
                 Tab source = getTabControl().getCurrentTab();
                 if (source == null) break;
-                Tab snapshot = createNewTab(false, false, false);
-                if (snapshot == null) break;
-                try {
-                    ByteArrayOutputStream bos = new ByteArrayOutputStream();
-                    source.saveSnapshot(bos);
-                    ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
-                    snapshot.loadSnapshot(bis);
-                    mUi.onTabDataChanged(snapshot);
-                    bis.close();
-                    bos.close();
-                    setActiveTab(snapshot);
-                } catch (IOException e) {
-                }
+                final ContentResolver cr = mActivity.getContentResolver();
+                final ContentValues values = source.createSnapshotValues();
+                new AsyncTask<Tab, Void, Long>() {
+                    @Override
+                    protected Long doInBackground(Tab... params) {
+                        Tab t = params[0];
+                        if (values == null) {
+                            return t.isSnapshot()
+                                    ? ((SnapshotTab)t).getSnapshotId()
+                                    : -1;
+                        }
+                        Uri result = cr.insert(Snapshots.CONTENT_URI, values);
+                        long id = ContentUris.parseId(result);
+                        return id;
+                    }
+
+                    protected void onPostExecute(Long id) {
+                        if (id > 0) {
+                            createNewSnapshotTab(id, true);
+                        }
+                    };
+                }.execute(source);
                 break;
 
             case R.id.save_webarchive_menu_id:
@@ -2139,6 +2153,18 @@ public class Controller
         mUi.removeTab(tab);
         mTabControl.removeTab(tab);
         mCrashRecoveryHandler.backupState();
+        if (tab.isSnapshot()) {
+            SnapshotTab st = (SnapshotTab) tab;
+            final Uri uri = ContentUris.withAppendedId(
+                    Snapshots.CONTENT_URI, st.getSnapshotId());
+            final ContentResolver cr = mActivity.getContentResolver();
+            new Thread() {
+                @Override
+                public void run() {
+                    cr.delete(uri, null, null);
+                }
+            }.start();
+        }
     }
 
     @Override
@@ -2281,6 +2307,15 @@ public class Controller
         return tab;
     }
 
+    private SnapshotTab createNewSnapshotTab(long snapshotId, boolean setActive) {
+        SnapshotTab tab = mTabControl.createSnapshotTab(snapshotId);
+        addTab(tab);
+        if (setActive) {
+            setActiveTab(tab);
+        }
+        return tab;
+    }
+
     /**
      * @param tab the tab to switch to
      * @return boolean True if we successfully switched to a different tab.  If
diff --git a/src/com/android/browser/NavTabView.java b/src/com/android/browser/NavTabView.java
index f170b0f..daa5013 100644
--- a/src/com/android/browser/NavTabView.java
+++ b/src/com/android/browser/NavTabView.java
@@ -49,7 +49,6 @@ public class NavTabView extends LinearLayout {
     private Drawable mUrlBg;
     private float mMediumTextSize;
     private float mSmallTextSize;
-    private boolean mPaused;
 
     public NavTabView(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
@@ -85,20 +84,6 @@ public class NavTabView extends LinearLayout {
         setState(false);
     }
 
-    protected void pause() {
-        mPaused = true;
-        mWebView.onPause();
-    }
-
-    protected void resume() {
-        mPaused = false;
-        mWebView.onResume();
-    }
-
-    protected boolean isPaused() {
-        return mPaused;
-    }
-
     protected boolean isRefresh(View v) {
         return v == mRefresh;
     }
@@ -128,10 +113,8 @@ public class NavTabView extends LinearLayout {
     private void setState(boolean highlighted) {
         if (highlighted) {
             setAlpha(1.0f);
-            mRefresh.setVisibility(View.VISIBLE);
             mFavicon.setVisibility(View.VISIBLE);
-            mForward.setVisibility(mWebView.canGoForward()
-                    ? View.VISIBLE : View.GONE);
+            setupButtons();
             mTitleBar.setBackgroundDrawable(mTitleBg);
             mClose.setVisibility(View.VISIBLE);
             mTitle.setTextSize(TypedValue.COMPLEX_UNIT_PX, mMediumTextSize);
@@ -166,18 +149,27 @@ public class NavTabView extends LinearLayout {
 
     protected void setWebView(PhoneUi ui, Tab tab) {
         mTab = tab;
+        mFavicon.setImageDrawable(ui.getFaviconDrawable(tab.getFavicon()));
+        setTitle();
         BrowserWebView web = (BrowserWebView) tab.getWebView();
-        if (web == null) return;
-        mWebView = web;
-        removeFromParent(mWebView);
-        mProxy = new WebProxyView(mContext, mWebView);
-        mContainer.addView(mProxy, 0);
-        if (mWebView != null) {
+        if (web != null) {
+            mWebView = web;
+            removeFromParent(mWebView);
+            mProxy = new WebProxyView(mContext, mWebView);
+            mContainer.addView(mProxy, 0);
+        }
+        setupButtons();
+    }
+
+    void setupButtons() {
+        if (mTab.isSnapshot()) {
+            mForward.setVisibility(View.GONE);
+            mRefresh.setVisibility(View.GONE);
+        } else if (mWebView != null) {
             mForward.setVisibility(mWebView.canGoForward()
                     ? View.VISIBLE : View.GONE);
+            mRefresh.setVisibility(View.VISIBLE);
         }
-        mFavicon.setImageDrawable(ui.getFaviconDrawable(tab.getFavicon()));
-        setTitle();
     }
 
     protected void hideTitle() {
diff --git a/src/com/android/browser/SnapshotTab.java b/src/com/android/browser/SnapshotTab.java
new file mode 100644
index 0000000..52a5c5f
--- /dev/null
+++ b/src/com/android/browser/SnapshotTab.java
@@ -0,0 +1,163 @@
+/*
+ * Copyright (C) 2011 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.browser;
+
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.graphics.BitmapFactory;
+import android.graphics.Color;
+import android.net.Uri;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.webkit.WebView;
+
+import com.android.browser.provider.BrowserProvider2.Snapshots;
+
+import java.io.ByteArrayInputStream;
+
+
+public class SnapshotTab extends Tab {
+
+    private long mSnapshotId;
+    private LoadData mLoadTask;
+    private WebViewFactory mWebViewFactory;
+    // TODO: Support non-persistent webview's on phone
+    private boolean mPersistentWebview;
+    private int mBackgroundColor;
+
+    public SnapshotTab(WebViewController wvcontroller, long snapshotId) {
+        super(wvcontroller, null);
+        mSnapshotId = snapshotId;
+        mWebViewFactory = mWebViewController.getWebViewFactory();
+        mPersistentWebview = !BrowserActivity.isTablet(wvcontroller.getActivity());
+        if (mPersistentWebview) {
+            WebView web = mWebViewFactory.createWebView(false);
+            setWebView(web);
+        }
+        loadData();
+    }
+
+    @Override
+    void putInForeground() {
+        if (getWebView() == null) {
+            WebView web = mWebViewFactory.createWebView(false);
+            if (mBackgroundColor != 0) {
+                web.setBackgroundColor(mBackgroundColor);
+            }
+            setWebView(web);
+            loadData();
+        }
+        super.putInForeground();
+    }
+
+    @Override
+    void putInBackground() {
+        if (getWebView() == null) return;
+        super.putInBackground();
+        if (!mPersistentWebview) {
+            super.destroy();
+        }
+    }
+
+    void loadData() {
+        if (mLoadTask == null) {
+            mLoadTask = new LoadData(this, mActivity.getContentResolver());
+            mLoadTask.execute();
+        }
+    }
+
+    @Override
+    void addChildTab(Tab child) {
+        throw new IllegalStateException("Snapshot tabs cannot have child tabs!");
+    }
+
+    @Override
+    public boolean isSnapshot() {
+        return true;
+    }
+
+    public long getSnapshotId() {
+        return mSnapshotId;
+    }
+
+    @Override
+    public ContentValues createSnapshotValues() {
+        return null;
+    }
+
+    @Override
+    boolean saveState() {
+        return false;
+    }
+
+    static class LoadData extends AsyncTask<Void, Void, Cursor> {
+
+        static final String[] PROJECTION = new String[] {
+            Snapshots._ID, // 0
+            Snapshots.TITLE, // 1
+            Snapshots.URL, // 2
+            Snapshots.FAVICON, // 3
+            Snapshots.VIEWSTATE, // 4
+            Snapshots.BACKGROUND, // 5
+        };
+
+        private SnapshotTab mTab;
+        private ContentResolver mContentResolver;
+
+        public LoadData(SnapshotTab t, ContentResolver cr) {
+            mTab = t;
+            mContentResolver = cr;
+        }
+
+        @Override
+        protected Cursor doInBackground(Void... params) {
+            long id = mTab.mSnapshotId;
+            Uri uri = ContentUris.withAppendedId(Snapshots.CONTENT_URI, id);
+            return mContentResolver.query(uri, PROJECTION, null, null, null);
+        }
+
+        @Override
+        protected void onPostExecute(Cursor result) {
+            try {
+                if (result.moveToFirst()) {
+                    mTab.mCurrentState.mTitle = result.getString(1);
+                    mTab.mCurrentState.mUrl = result.getString(2);
+                    byte[] favicon = result.getBlob(3);
+                    if (favicon != null) {
+                        mTab.mCurrentState.mFavicon = BitmapFactory
+                                .decodeByteArray(favicon, 0, favicon.length);
+                    }
+                    WebView web = mTab.getWebView();
+                    if (web != null) {
+                        byte[] data = result.getBlob(4);
+                        ByteArrayInputStream stream = new ByteArrayInputStream(data);
+                        web.loadViewState(stream);
+                    }
+                    mTab.mBackgroundColor = result.getInt(5);
+                    mTab.mWebViewController.onPageFinished(mTab);
+                }
+            } finally {
+                if (result != null) {
+                    result.close();
+                }
+                mTab.mLoadTask = null;
+            }
+        }
+
+    }
+}
diff --git a/src/com/android/browser/Tab.java b/src/com/android/browser/Tab.java
index 89f567b..bb200d8 100644
--- a/src/com/android/browser/Tab.java
+++ b/src/com/android/browser/Tab.java
@@ -20,6 +20,8 @@ import android.app.Activity;
 import android.app.AlertDialog;
 import android.app.SearchManager;
 import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.DialogInterface.OnCancelListener;
@@ -62,6 +64,7 @@ import android.widget.TextView;
 import android.widget.Toast;
 
 import com.android.browser.homepages.HomeProvider;
+import com.android.browser.provider.BrowserProvider2.Snapshots;
 import com.android.common.speech.LoggingEvents;
 
 import java.io.ByteArrayOutputStream;
@@ -96,10 +99,10 @@ class Tab {
     }
 
     Activity mActivity;
-    private WebViewController mWebViewController;
+    protected WebViewController mWebViewController;
 
     // The tab ID
-    private long mId;
+    private long mId = -1;
 
     // The Geolocation permissions prompt
     private GeolocationPermissionsPrompt mGeolocationPermissionsPrompt;
@@ -145,7 +148,6 @@ class Tab {
     private DataController mDataController;
     // State of the auto-login request.
     private DeviceAccountLogin mDeviceAccountLogin;
-    private boolean mIsSnapshot = false;
 
     // AsyncTask for downloading touch icons
     DownloadTouchIcon mTouchIconLoader;
@@ -154,7 +156,7 @@ class Tab {
     private BrowserSettings mSettings;
 
     // All the state needed for a page
-    private static class PageState {
+    protected static class PageState {
         String mUrl;
         String mTitle;
         LockIcon mLockIcon;
@@ -192,7 +194,7 @@ class Tab {
     }
 
     // The current/loading page's state
-    private PageState mCurrentState;
+    protected PageState mCurrentState;
 
     // Used for saving and restoring each Tab
     static final String ID = "ID";
@@ -1512,10 +1514,6 @@ class Tab {
      * @param child the Tab that was created from this Tab
      */
     void addChildTab(Tab child) {
-        if (mIsSnapshot) {
-            throw new IllegalStateException(
-                    "Snapshot tabs cannot have child tabs!");
-        }
         if (mChildren == null) {
             mChildren = new Vector<Tab>();
         }
@@ -1846,100 +1844,23 @@ class Tab {
     }
 
     public boolean isSnapshot() {
-        return mIsSnapshot;
-    }
-
-    public boolean loadSnapshot(InputStream rstream) {
-        if (rstream == null) {
-            mIsSnapshot = false;
-            if (mMainView != null) {
-                mMainView.clearViewState();
-            }
-            return true;
-        }
-        DataInputStream stream = new DataInputStream(rstream);
-        if (!readTabInfo(stream)) {
-            return false;
-        }
-        if (!mMainView.loadViewState(stream)) {
-            return false;
-        }
-        mIsSnapshot = true;
-        return true;
-    }
-
-    public boolean saveSnapshot(OutputStream rstream) {
-        if (rstream == null) return false;
-        if (mMainView == null) return false;
-        DataOutputStream stream = new DataOutputStream(rstream);
-        if (saveTabInfo(stream)) {
-            return mMainView.saveViewState(stream);
-        }
         return false;
     }
 
-    private boolean readTabInfo(DataInputStream stream) {
-        try {
-            PageState state = new PageState(mActivity, false);
-            state.mTitle = stream.readUTF();
-            if (state.mTitle.length() == 0) {
-                state.mTitle = null;
-            }
-            state.mUrl = stream.readUTF();
-            int faviconLen = stream.readInt();
-            if (faviconLen > 0) {
-                byte[] data = new byte[faviconLen];
-                int read = stream.read(data);
-                if (read != faviconLen) {
-                    throw new IOException("Read didn't match expected len!"
-                            + " Expected: " + faviconLen
-                            + " Got: " + read);
-                }
-                state.mFavicon = BitmapFactory.decodeByteArray(data, 0, data.length);
-            }
-            mCurrentState = state;
-            return true;
-        } catch (IOException e) {
-            return false;
-        }
-    }
-
-    private boolean saveTabInfo(DataOutputStream stream) {
-        try {
-            // mTitle might be null, but writeUTF doesn't handle that
-            String title = mCurrentState.mTitle;
-            stream.writeUTF(title != null ? title : "");
-            // mUrl is never null
-            stream.writeUTF(mCurrentState.mUrl);
-            byte[] compressedPixels = compressFavicon();
-            if (compressedPixels == null) {
-                stream.writeInt(-1);
-            } else {
-                stream.writeInt(compressedPixels.length);
-                stream.write(compressedPixels);
-            }
-            return true;
-        } catch (Exception e) {
-            Log.w(LOGTAG, "Failed to saveTabInfo", e);
-            return false;
-        }
-    }
-
-    private byte[] compressFavicon() {
-        Bitmap favicon = mCurrentState.mFavicon;
-        if (favicon == null) {
+    public ContentValues createSnapshotValues() {
+        if (mMainView == null) return null;
+        ByteArrayOutputStream stream = new ByteArrayOutputStream();
+        if (!mMainView.saveViewState(stream)) {
             return null;
         }
-        ByteArrayOutputStream stream = new ByteArrayOutputStream();
-        byte[] data = null;
-        try {
-            favicon.compress(CompressFormat.PNG, 100, stream);
-            data = stream.toByteArray();
-            stream.close();
-        } catch (IOException e) {
-            // Will return null below then
-        }
-        return data;
+        byte[] data = stream.toByteArray();
+        ContentResolver cr = mActivity.getContentResolver();
+        ContentValues values = new ContentValues();
+        values.put(Snapshots.TITLE, mCurrentState.mTitle);
+        values.put(Snapshots.URL, mCurrentState.mUrl);
+        values.put(Snapshots.VIEWSTATE, data);
+        values.put(Snapshots.BACKGROUND, mMainView.getPageBackgroundColor());
+        return values;
     }
 
 }
diff --git a/src/com/android/browser/TabControl.java b/src/com/android/browser/TabControl.java
index 1e21431..6566ac8 100644
--- a/src/com/android/browser/TabControl.java
+++ b/src/com/android/browser/TabControl.java
@@ -16,10 +16,14 @@
 
 package com.android.browser;
 
+import android.content.ContentResolver;
+import android.database.Cursor;
 import android.os.Bundle;
 import android.util.Log;
 import android.webkit.WebView;
 
+import com.android.browser.provider.BrowserProvider2.Snapshots;
+
 import java.io.File;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -30,8 +34,8 @@ class TabControl {
     // Log Tag
     private static final String LOGTAG = "TabControl";
 
-    // next Tab ID
-    private static long sNextId = 0;
+    // next Tab ID, starting at 1
+    private static long sNextId = 1;
 
     private static final String POSITIONS = "positions";
     private static final String CURRENT = "current";
@@ -202,6 +206,14 @@ class TabControl {
         return createNewTab(false);
     }
 
+    SnapshotTab createSnapshotTab(long snapshotId) {
+        // TODO: Don't count this against the limit
+        SnapshotTab t = new SnapshotTab(mController, snapshotId);
+        t.setId(getNextId());
+        mTabs.add(t);
+        return t;
+    }
+
     /**
      * Remove the parent child relationships from all tabs.
      */
@@ -346,7 +358,10 @@ class TabControl {
             }
             final String idkey = Long.toString(id);
             Bundle state = inState.getBundle(idkey);
-            if (!restoreIncognitoTabs && state != null
+            if (state == null || state.isEmpty()) {
+                // Skip tab
+                continue;
+            } else if (!restoreIncognitoTabs
                     && state.getBoolean(Tab.INCOGNITO)) {
                 // ignore tab
             } else if (id == currentId || restoreAll) {
@@ -383,6 +398,16 @@ class TabControl {
             sNextId = maxId + 1;
 
         }
+        if (mCurrentTab == -1) {
+            if (getTabCount() > 0) {
+                setCurrentTab(getTab(0));
+            } else {
+                Tab t = createNewTab();
+                setCurrentTab(t);
+                t.getWebView().loadUrl(BrowserSettings.getInstance()
+                        .getHomePage());
+            }
+        }
         // restore parent/child relationships
         for (long id : ids) {
             final Tab tab = tabMap.get(id);
@@ -397,6 +422,21 @@ class TabControl {
                 }
             }
         }
+        loadSnapshotTabs();
+
+    }
+
+    void loadSnapshotTabs() {
+        ContentResolver cr = mController.getActivity().getContentResolver();
+        Cursor c = cr.query(Snapshots.CONTENT_URI, new String[] { "_id" },
+                null, null, null);
+        try {
+            while (c.moveToNext()) {
+                createSnapshotTab(c.getLong(0));
+            }
+        } finally {
+            c.close();
+        }
     }
 
     /**
@@ -614,7 +654,7 @@ class TabControl {
         // Display the new current tab
         mCurrentTab = mTabs.indexOf(newTab);
         WebView mainView = newTab.getWebView();
-        boolean needRestore = (mainView == null);
+        boolean needRestore = !newTab.isSnapshot() && (mainView == null);
         if (needRestore) {
             // Same work as in createNewTab() except don't do new Tab()
             mainView = createNewWebView();
diff --git a/src/com/android/browser/provider/BrowserProvider2.java b/src/com/android/browser/provider/BrowserProvider2.java
index d9760e5..9f6e41c 100644
--- a/src/com/android/browser/provider/BrowserProvider2.java
+++ b/src/com/android/browser/provider/BrowserProvider2.java
@@ -16,15 +16,6 @@
 
 package com.android.browser.provider;
 
-import com.google.common.annotations.VisibleForTesting;
-
-import com.android.browser.BookmarkUtils;
-import com.android.browser.BrowserBookmarksPage;
-import com.android.browser.R;
-import com.android.browser.UrlUtils;
-import com.android.browser.widget.BookmarkThumbnailWidgetProvider;
-import com.android.common.content.SyncStateContentProviderHelper;
-
 import android.accounts.Account;
 import android.app.SearchManager;
 import android.content.ContentResolver;
@@ -32,7 +23,6 @@ import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.Context;
 import android.content.Intent;
-import android.content.SharedPreferences;
 import android.content.UriMatcher;
 import android.content.res.Resources;
 import android.content.res.TypedArray;
@@ -45,7 +35,6 @@ import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
 import android.database.sqlite.SQLiteQueryBuilder;
 import android.net.Uri;
-import android.preference.PreferenceManager;
 import android.provider.BaseColumns;
 import android.provider.Browser;
 import android.provider.Browser.BookmarkColumns;
@@ -63,6 +52,12 @@ import android.provider.ContactsContract.RawContacts;
 import android.provider.SyncStateContract;
 import android.text.TextUtils;
 
+import com.android.browser.R;
+import com.android.browser.UrlUtils;
+import com.android.browser.widget.BookmarkThumbnailWidgetProvider;
+import com.android.common.content.SyncStateContentProviderHelper;
+import com.google.common.annotations.VisibleForTesting;
+
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
@@ -72,6 +67,18 @@ import java.util.HashMap;
 
 public class BrowserProvider2 extends SQLiteContentProvider {
 
+    public static interface Snapshots {
+
+        public static final Uri CONTENT_URI = Uri.withAppendedPath(
+                BrowserContract.AUTHORITY_URI, "snapshots");
+        public static final String _ID = "_id";
+        public static final String VIEWSTATE = "view_state";
+        public static final String BACKGROUND = "background";
+        public static final String TITLE = History.TITLE;
+        public static final String URL = History.URL;
+        public static final String FAVICON = History.FAVICON;
+    }
+
     public static final String LEGACY_AUTHORITY = "browser";
     static final Uri LEGACY_AUTHORITY_URI = new Uri.Builder()
             .authority(LEGACY_AUTHORITY).scheme("content").build();
@@ -82,6 +89,7 @@ public class BrowserProvider2 extends SQLiteContentProvider {
     static final String TABLE_SEARCHES = "searches";
     static final String TABLE_SYNC_STATE = "syncstate";
     static final String TABLE_SETTINGS = "settings";
+    static final String TABLE_SNAPSHOTS = "snapshots";
 
     static final String TABLE_BOOKMARKS_JOIN_IMAGES = "bookmarks LEFT OUTER JOIN images " +
             "ON bookmarks.url = images." + Images.URL;
@@ -89,6 +97,7 @@ public class BrowserProvider2 extends SQLiteContentProvider {
             "ON history.url = images." + Images.URL;
 
     static final String VIEW_ACCOUNTS = "v_accounts";
+    static final String VIEW_SNAPSHOTS_COMBINED = "v_snapshots_combined";
 
     static final String FORMAT_COMBINED_JOIN_SUBQUERY_JOIN_IMAGES =
             "history LEFT OUTER JOIN (%s) bookmarks " +
@@ -139,6 +148,9 @@ public class BrowserProvider2 extends SQLiteContentProvider {
     static final int LEGACY = 9000;
     static final int LEGACY_ID = 9001;
 
+    static final int SNAPSHOTS = 10000;
+    static final int SNAPSHOTS_ID = 10001;
+
     public static final long FIXED_ID_ROOT = 1;
 
     // Default sort order for unsync'd bookmarks
@@ -200,6 +212,9 @@ public class BrowserProvider2 extends SQLiteContentProvider {
                 "bookmarks/" + SearchManager.SUGGEST_URI_PATH_QUERY,
                 BOOKMARKS_SUGGESTIONS);
 
+        matcher.addURI(authority, "snapshots", SNAPSHOTS);
+        matcher.addURI(authority, "snapshots/#", SNAPSHOTS_ID);
+
         // Projection maps
         HashMap<String, String> map;
 
@@ -333,7 +348,7 @@ public class BrowserProvider2 extends SQLiteContentProvider {
 
     final class DatabaseHelper extends SQLiteOpenHelper {
         static final String DATABASE_NAME = "browser2.db";
-        static final int DATABASE_VERSION = 28;
+        static final int DATABASE_VERSION = 29;
         public DatabaseHelper(Context context) {
             super(context, DATABASE_NAME, null, DATABASE_VERSION);
         }
@@ -404,6 +419,8 @@ public class BrowserProvider2 extends SQLiteContentProvider {
             }
 
             enableSync(db);
+
+            createSnapshots(db);
         }
 
         void enableSync(SQLiteDatabase db) {
@@ -500,6 +517,9 @@ public class BrowserProvider2 extends SQLiteContentProvider {
 
         @Override
         public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+            if (oldVersion < 29) {
+                createSnapshots(db);
+            }
             if (oldVersion < 28) {
                 enableSync(db);
             }
@@ -520,6 +540,22 @@ public class BrowserProvider2 extends SQLiteContentProvider {
             }
         }
 
+        void createSnapshots(SQLiteDatabase db) {
+            db.execSQL("DROP TABLE IF EXISTS " + TABLE_SNAPSHOTS);
+            db.execSQL("CREATE TABLE " + TABLE_SNAPSHOTS + " (" +
+                    Snapshots._ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
+                    Snapshots.URL + " TEXT NOT NULL," +
+                    Snapshots.TITLE + " TEXT," +
+                    Snapshots.BACKGROUND + " INTEGER," +
+                    Snapshots.VIEWSTATE + " BLOB NOT NULL" +
+                    ");");
+            db.execSQL("CREATE VIEW IF NOT EXISTS " + VIEW_SNAPSHOTS_COMBINED +
+                    " AS SELECT * FROM " + TABLE_SNAPSHOTS +
+                    " LEFT OUTER JOIN " + TABLE_IMAGES +
+                    " ON " + TABLE_SNAPSHOTS + "." + Snapshots.URL +
+                    " = images.url_key");
+        }
+
         @Override
         public void onOpen(SQLiteDatabase db) {
             db.enableWriteAheadLogging();
@@ -970,6 +1006,17 @@ public class BrowserProvider2 extends SQLiteContentProvider {
                 break;
             }
 
+            case SNAPSHOTS_ID: {
+                selection = DatabaseUtils.concatenateWhere(selection, "_id=?");
+                selectionArgs = DatabaseUtils.appendSelectionArgs(selectionArgs,
+                        new String[] { Long.toString(ContentUris.parseId(uri)) });
+                // fall through
+            }
+            case SNAPSHOTS: {
+                qb.setTables(VIEW_SNAPSHOTS_COMBINED);
+                break;
+            }
+
             default: {
                 throw new UnsupportedOperationException("Unknown URL " + uri.toString());
             }
@@ -1169,6 +1216,16 @@ public class BrowserProvider2 extends SQLiteContentProvider {
                 }
                 break;
             }
+            case SNAPSHOTS_ID: {
+                selection = DatabaseUtils.concatenateWhere(selection, TABLE_SNAPSHOTS + "._id=?");
+                selectionArgs = DatabaseUtils.appendSelectionArgs(selectionArgs,
+                        new String[] { Long.toString(ContentUris.parseId(uri)) });
+                // fall through
+            }
+            case SNAPSHOTS: {
+                deleted = db.delete(TABLE_SNAPSHOTS, selection, selectionArgs);
+                break;
+            }
             default: {
                 throw new UnsupportedOperationException("Unknown delete URI " + uri);
             }
@@ -1301,6 +1358,11 @@ public class BrowserProvider2 extends SQLiteContentProvider {
                 break;
             }
 
+            case SNAPSHOTS: {
+                id = db.insertOrThrow(TABLE_SNAPSHOTS, Snapshots.TITLE, values);
+                break;
+            }
+
             default: {
                 throw new UnsupportedOperationException("Unknown insert URI " + uri);
             }