[scheduler] Changing serial AsyncTask to SequencedTaskRunner.

Bug: 863341
Change-Id: I47e06b340428875125a139f764d2dae570a9eafc
Reviewed-on: https://chromium-review.googlesource.com/c/1478874
Commit-Queue: Karolina Soltys <ksolt@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635960}

android_webview/java/src/org/chromium/android_webview/AwBrowserProcess.java

@@ -28,8 +28,9 @@ import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.library_loader.LibraryLoader;
 import org.chromium.base.library_loader.LibraryProcessType;
 import org.chromium.base.library_loader.ProcessInitException;
-import org.chromium.base.task.AsyncTask;
-import org.chromium.base.task.BackgroundOnlyAsyncTask;
+import org.chromium.base.task.PostTask;
+import org.chromium.base.task.TaskRunner;
+import org.chromium.base.task.TaskTraits;
 import org.chromium.components.minidump_uploader.CrashFileManager;
 import org.chromium.content_public.browser.BrowserStartupController;
 import org.chromium.content_public.browser.ChildProcessCreationParams;
@@ -51,10 +52,22 @@ public final class AwBrowserProcess {
 
     private static final String WEBVIEW_DIR_BASENAME = "webview";
     private static final String EXCLUSIVE_LOCK_FILE = "webview_data.lock";
+
+    // To avoid any potential synchronization issues we post all minidump-copying actions to
+    // the same sequence to be run serially.
+    private static final TaskRunner sSequencedTaskRunner =
+            PostTask.createSequencedTaskRunner(TaskTraits.BEST_EFFORT_MAY_BLOCK);
+
     private static RandomAccessFile sLockFile;
     private static FileLock sExclusiveFileLock;
     private static String sWebViewPackageName;
 
+    // TODO(ksolt): This is a temporary solution to avoid lifetime check errors.
+    // Will be fixed after we decide how to handle the destruction of static TaskRunners.
+    static {
+        sSequencedTaskRunner.disableLifetimeCheck();
+    }
+
     /**
      * Loads the native library, and performs basic static construction of objects needed
      * to run webview in this process. Does not create threads; safe to call from zygote.
@@ -229,19 +242,17 @@ public final class AwBrowserProcess {
      * minidumps, if we don't, delete them.
      */
     public static void handleMinidumps(final boolean userApproved) {
-        new BackgroundOnlyAsyncTask<Void>() {
-            @Override
-            protected Void doInBackground() {
+        sSequencedTaskRunner.postTask(() -> {
             final Context appContext = ContextUtils.getApplicationContext();
             final File crashSpoolDir = new File(appContext.getCacheDir().getPath(), "WebView");
-                if (!crashSpoolDir.isDirectory()) return null;
+            if (!crashSpoolDir.isDirectory()) return;
             final CrashFileManager crashFileManager = new CrashFileManager(crashSpoolDir);
 
             // The lifecycle of a minidump in the app directory is very simple: foo.dmpNNNNN --
             // where NNNNN is a Process ID (PID) -- gets created, and is either deleted or
             // copied over to the shared crash directory for all WebView-using apps.
             final File[] minidumpFiles = crashFileManager.getMinidumpsSansLogcat();
-                if (minidumpFiles.length == 0) return null;
+            if (minidumpFiles.length == 0) return;
 
             // Delete the minidumps if the user doesn't allow crash data uploading.
             if (!userApproved) {
@@ -250,7 +261,7 @@ public final class AwBrowserProcess {
                         Log.w(TAG, "Couldn't delete file " + minidump.getAbsolutePath());
                     }
                 }
-                    return null;
+                return;
             }
 
             final Intent intent = new Intent();
@@ -277,7 +288,8 @@ public final class AwBrowserProcess {
                                 minidumpFds[i] = null; // This is slightly ugly :)
                             }
                             if (!minidumpFiles[i].delete()) {
-                                    Log.w(TAG, "Couldn't delete file "
+                                Log.w(TAG,
+                                        "Couldn't delete file "
                                                 + minidumpFiles[i].getAbsolutePath());
                             }
                         }
@@ -306,11 +318,7 @@ public final class AwBrowserProcess {
             if (!appContext.bindService(intent, connection, Context.BIND_AUTO_CREATE)) {
                 Log.w(TAG, "Could not bind to Minidump-copying Service " + intent);
             }
-                return null;
-            }
-            // To avoid any potential synchronization issues we post all minidump-copying actions to
-            // the same thread to be run serially.
-        }.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR);
+        });
     }
 
     // Do not instantiate this class.