Bug 1674428 - Part 2. Add method to collect files that is selected WebKitDirectory. r=dom-core,sefeng

When using Android 13 or later, there is no permission to enumerate
directories if on user storage. So `GetFilesHelper` and etc won't work on
Android.

We have to use content resolver APIs to enumerate files in directory.
So I have to add a method to collect files in FilePicker and return
DOM Files.

Differential Revision: https://phabricator.services.mozilla.com/D228761

dom/html/HTMLInputElement.cpp

@@ -576,6 +576,36 @@ HTMLInputElement::nsFilePickerShownCallback::Done(
 
   if (StaticPrefs::dom_webkitBlink_dirPicker_enabled() &&
       mInput->HasAttr(nsGkAtoms::webkitdirectory)) {
+#ifdef MOZ_WIDGET_ANDROID
+    // Android 13 or later cannot enumerate files into user directory due to
+    // no permission. So we store file list into file picker.
+    FallibleTArray<RefPtr<BlobImpl>> filesInWebKitDirectory;
+
+    nsCOMPtr<nsISimpleEnumerator> iter;
+    if (NS_SUCCEEDED(
+            mFilePicker->GetDomFilesInWebKitDirectory(getter_AddRefs(iter))) &&
+        iter) {
+      nsCOMPtr<nsISupports> supports;
+
+      bool loop = true;
+      while (NS_SUCCEEDED(iter->HasMoreElements(&loop)) && loop) {
+        iter->GetNext(getter_AddRefs(supports));
+        if (supports) {
+          RefPtr<BlobImpl> file = static_cast<File*>(supports.get())->Impl();
+          MOZ_ASSERT(file);
+          if (!filesInWebKitDirectory.AppendElement(file, fallible)) {
+            return nsresult::NS_ERROR_OUT_OF_MEMORY;
+          }
+        }
+      }
+    }
+
+    if (!filesInWebKitDirectory.IsEmpty()) {
+      dispatchChangeEventCallback->Callback(NS_OK, filesInWebKitDirectory);
+      return NS_OK;
+    }
+#endif
+
     ErrorResult error;
     GetFilesHelper* helper = mInput->GetOrCreateGetFilesHelper(true, error);
     if (NS_WARN_IF(error.Failed())) {