[Android Webapp] Fix potential concurrency issue with WebappDataStorage

ProcessInitializationHandler#handleDeferredStartupTasksInitialization() and
WebApkUma#recordDeferredUma() call WebappRegistry#warmUpSharedPrefs()
from the background thread and the UI thread respectively. Both calls occur
from DeferredStartupHandler

This CL changes WebappRegistry#initStorages() to mutate
WebappRegistry#mStorages on the UI thread.

BUG=1000949

Change-Id: I71ec4d049000d67a4052502c72da62a2ce1aadf6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1801989
Commit-Queue: Peter Kotwicz <pkotwicz@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696943}

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappRegistry.java

@@ -8,16 +8,20 @@ import android.content.Context;
 import android.content.SharedPreferences;
 import android.text.TextUtils;
 import android.text.format.DateUtils;
+import android.util.Pair;
 
 import org.chromium.base.ContextUtils;
 import org.chromium.base.PackageUtils;
 import org.chromium.base.StrictModeContext;
+import org.chromium.base.ThreadUtils;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.task.AsyncTask;
+import org.chromium.base.task.PostTask;
 import org.chromium.chrome.browser.browserservices.permissiondelegation.TrustedWebActivityPermissionStore;
 import org.chromium.chrome.browser.browsing_data.UrlFilter;
 import org.chromium.chrome.browser.browsing_data.UrlFilterBridge;
+import org.chromium.content_public.browser.UiThreadTaskTraits;
 import org.chromium.webapk.lib.common.WebApkConstants;
 
 import java.util.ArrayList;
@@ -60,6 +64,8 @@ public class WebappRegistry {
         private static WebappRegistry sInstance = new WebappRegistry();
     }
 
+    private boolean mIsInitialized;
+
     private HashMap<String, WebappDataStorage> mStorages;
     private SharedPreferences mPreferences;
     private TrustedWebActivityPermissionStore mTrustedWebActivityPermissionStore;
@@ -93,24 +99,27 @@ public class WebappRegistry {
     }
 
     /**
-     * Warm up the WebappRegistry and a specific WebappDataStorage SharedPreferences.
+     * Warm up the WebappRegistry and a specific WebappDataStorage SharedPreferences. Can be called
+     * from any thread.
      * @param id The web app id to warm up in addition to the WebappRegistry.
      */
     public static void warmUpSharedPrefsForId(String id) {
-        getInstance().initStorages(id, false);
+        getInstance().initStorages(id);
     }
 
     /**
-     * Warm up the WebappRegistry and all WebappDataStorage SharedPreferences.
+     * Warm up the WebappRegistry and all WebappDataStorage SharedPreferences. Can be called from
+     * any thread.
      */
     public static void warmUpSharedPrefs() {
-        getInstance().initStorages(null, false);
+        getInstance().initStorages(null);
     }
 
     @VisibleForTesting
     public static void refreshSharedPrefsForTesting() {
         Holder.sInstance = new WebappRegistry();
-        getInstance().initStorages(null, true);
+        getInstance().clearStoragesForTesting();
+        getInstance().initStorages(null);
     }
 
     /**
@@ -343,23 +352,45 @@ public class WebappRegistry {
         }
     }
 
-    private void initStorages(String idToInitialize, boolean replaceExisting) {
+    private void clearStoragesForTesting() {
+        ThreadUtils.assertOnUiThread();
+        mStorages.clear();
+    }
+
+    private void initStorages(String idToInitialize) {
         Set<String> webapps = mPreferences.getStringSet(KEY_WEBAPP_SET, Collections.emptySet());
         boolean initAll = (idToInitialize == null || idToInitialize.isEmpty());
 
-        // Don't overwrite any entry in mStorages unless replaceExisting is set to true.
+        if (initAll && !mIsInitialized) {
+            mTrustedWebActivityPermissionStore.initStorage();
+            mIsInitialized = true;
+        }
+
+        List<Pair<String, WebappDataStorage>> initedStorages =
+                new ArrayList<Pair<String, WebappDataStorage>>();
         if (initAll) {
             for (String id : webapps) {
-                if (replaceExisting || !mStorages.containsKey(id)) {
-                    mStorages.put(id, WebappDataStorage.open(id));
+                if (!mStorages.containsKey(id)) {
+                    initedStorages.add(Pair.create(id, WebappDataStorage.open(id)));
                 }
             }
-
-            mTrustedWebActivityPermissionStore.initStorage();
         } else {
-            if (webapps.contains(idToInitialize)
-                    && (replaceExisting || !mStorages.containsKey(idToInitialize))) {
-                mStorages.put(idToInitialize, WebappDataStorage.open(idToInitialize));
+            if (webapps.contains(idToInitialize) && !mStorages.containsKey(idToInitialize)) {
+                initedStorages.add(
+                        Pair.create(idToInitialize, WebappDataStorage.open(idToInitialize)));
+            }
+        }
+
+        PostTask.runOrPostTask(
+                UiThreadTaskTraits.DEFAULT, () -> { initStoragesOnUiThread(initedStorages); });
+    }
+
+    private void initStoragesOnUiThread(List<Pair<String, WebappDataStorage>> initedStorages) {
+        ThreadUtils.assertOnUiThread();
+
+        for (Pair<String, WebappDataStorage> initedStorage : initedStorages) {
+            if (!mStorages.containsKey(initedStorage.first)) {
+                mStorages.put(initedStorage.first, initedStorage.second);
             }
         }
     }

chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappModeTest.java

@@ -38,6 +38,7 @@ import org.chromium.chrome.test.util.ApplicationTestUtils;
 import org.chromium.chrome.test.util.browser.webapps.WebappTestHelper;
 import org.chromium.content_public.browser.test.util.Criteria;
 import org.chromium.content_public.browser.test.util.CriteriaHelper;
+import org.chromium.content_public.browser.test.util.TestThreadUtils;
 
 /**
  * Tests that WebappActivities are launched correctly.
@@ -99,11 +100,12 @@ public class WebappModeTest {
 
     @Before
     public void setUp() throws Exception {
+        TestThreadUtils.runOnUiThreadBlocking(() -> {
             WebappRegistry.refreshSharedPrefsForTesting();
 
-        // Register the webapps so when the data storage is opened, the test doesn't crash. There is
-        // no race condition with the retrieval as AsyncTasks are run sequentially on the background
-        // thread.
+            // Register the webapps so when the data storage is opened, the test doesn't crash.
+            // There is no race condition with the retrieval as AsyncTasks are run sequentially on
+            // the background thread.
             WebappRegistry.getInstance().register(
                     WEBAPP_1_ID, new WebappRegistry.FetchWebappDataStorageCallback() {
                         @Override
@@ -120,6 +122,7 @@ public class WebappModeTest {
                                     WEBAPP_1_ID, WEBAPP_1_URL, WEBAPP_1_TITLE, WEBAPP_ICON, true));
                         }
                     });
+        });
     }
 
     /**
@@ -319,7 +322,7 @@ public class WebappModeTest {
                 Activity lastActivity = ApplicationStatus.getLastTrackedFocusedActivity();
                 return isWebappActivityReady(lastActivity);
             }
-        });
+        }, 10000, CriteriaHelper.DEFAULT_POLLING_INTERVAL);
         return (WebappActivity) ApplicationStatus.getLastTrackedFocusedActivity();
     }