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
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;
+            }
+        }
+
+    }
+}