DownloadDirectoryProvider: getUiThreadHandler -> PostTask

Part of an ongoing effort of ThreadUtils --> PostTask migration.

Bug: 863341
Change-Id: I2feb4d7dc6280da16d25e91f75f8b10266bb3fcf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1448219Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Auto-Submit: Karolina Soltys <ksolt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638235}

chrome/android/java/src/org/chromium/chrome/browser/download/DownloadDirectoryProvider.java

@@ -10,15 +10,15 @@ import android.content.Intent;
 import android.content.IntentFilter;
 import android.os.Build;
 import android.os.Environment;
-import android.os.Handler;
 
 import org.chromium.base.Callback;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.PathUtils;
-import org.chromium.base.ThreadUtils;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.task.AsyncTask;
+import org.chromium.base.task.PostTask;
 import org.chromium.chrome.browser.download.DirectoryOption.DownloadLocationDirectoryType;
+import org.chromium.content_public.browser.UiThreadTaskTraits;
 
 import java.io.File;
 import java.util.ArrayList;
@@ -161,9 +161,6 @@ public class DownloadDirectoryProvider {
     private String mExternalStorageDirectory;
     private ArrayList < Callback < ArrayList<DirectoryOption>>> mCallbacks = new ArrayList<>();
 
-    // Should be bounded to UI thread.
-    protected final Handler mHandler = new Handler(ThreadUtils.getUiThreadLooper());
-
     protected DownloadDirectoryProvider() {
         registerSDCardReceiver();
     }
@@ -175,7 +172,8 @@ public class DownloadDirectoryProvider {
     public void getAllDirectoriesOptions(Callback<ArrayList<DirectoryOption>> callback) {
         // Use cache value.
         if (!mNeedsUpdate && mDirectoriesReady) {
-            mHandler.post(() -> callback.onResult(mDirectoryOptions));
+            PostTask.postTask(
+                    UiThreadTaskTraits.DEFAULT, () -> callback.onResult(mDirectoryOptions));
             return;
         }
 

chrome/android/javatests/src/org/chromium/chrome/browser/download/TestDownloadDirectoryProvider.java

@@ -5,6 +5,8 @@
 package org.chromium.chrome.browser.download;
 
 import org.chromium.base.Callback;
+import org.chromium.base.task.PostTask;
+import org.chromium.content_public.browser.UiThreadTaskTraits;
 
 import java.util.ArrayList;
 
@@ -22,6 +24,6 @@ public class TestDownloadDirectoryProvider extends DownloadDirectoryProvider {
     // DownloadDirectoryProvider implementation.
     @Override
     public void getAllDirectoriesOptions(Callback<ArrayList<DirectoryOption>> callback) {
-        mHandler.post(() -> callback.onResult(mDirectoryOptions));
+        PostTask.postTask(UiThreadTaskTraits.DEFAULT, () -> callback.onResult(mDirectoryOptions));
     }
-}
\ No newline at end of file
+}