import changes from `dev' branch of rmottola/Arctic-Fox:

- Bug 912337 - Followup: fix missing #include on a CLOSED TREE. (da77dc4ba0)
- Bug 1232977 - Remove redundant bitand with uint{8,16} and an all-bits-set mask. r=nbp, r=sunfish (164579d9d7)
- Bug 1249235 - Store RegExp flags into single slot. r=h4writer (6f030c9f06)
- Bug 1237445 - Use GCHashSet for RegExpShared sweeping, r=terrence (3aab1397e8)
- Bug 1238536 part 1 - Do not automatically exit fullscreen if restored from minimized state. r=jimm (05dd086d29)
- Bug 1238536 part 2 - Do not trigger fullscreen changed when switching between fullscreen and minimized. r=karlt (83e862cc7a)
- Bug 1233598 - HTMLInputElement must traverse/unlink the getFilesAndDirectories promise, r=smaug (1ff7260803)
- Bug 1187157 - new FormData::get() should return an empty string if the file is not set - part 1, r=smaug (9a255fd884)
- Bug 1187157 - new FormData::get() should return an empty string if the file is not set - part 2, r=smaug (f26712d951)
- Bug 1216793 - check against tracking protection list in XHR. r=gcp (3a827250bc)
- Bug 1203588 - Return the same Promise object from HTMLInputElement.getFilesAndDirectories when possible. r=baku (f036876c1b)
- Bug 1207088 - Don't show the "Choose folder..." button for a directory picking <input> on platforms that don't have a directory picker. r=jfkthame (c5742f75c9)
- Bug 1234192 - OSFileSystem should not be shared between Directory objects, r=smaug (ba258935b7)
- Bug 1202964 - Use the correct nsIFilePicker API for directory picking in HTMLInputElement::nsFilePickerShownCallback::Done. r=baku (ce11a83ace)
- Bug 1237674 - Rename nsFormData to mozilla::dom::FormData, r=smaug (0a18825b2b)
- Bug 1237595 - FormData ctor and form submission should create empty Blob/File when a input type=file is not set, r=smaug (2bce85bbe8)
- cleanup some stuff (cbd553db88)
- Bug 1238515 - nsIFilePicker methods should clearly say when they return directories and files, r=smaug (e903765f0c)
- Bug 1198256 - Replace deprecated GtkColorSelectionDialog with GtkColorChooserDialog in Gtk3. r=karlt (2ff87896a6)
- Bug 1198256 - Reactivate the old Gtk color picker for now. r=karlt (ea42685de9)
- Bug 1213632: Prevent WebExtensions from using versioned JavaScript. r=billm (9d3a9b7511)
- Bug 1219855, Part 1 - Make nsXULAlerts implement nsIAlertsService. r=MattN,wchen (6b21425554)
- Bug 1219855, Part 2 - Always use XUL notifications if the system backend fails. r=wchen (7c5b30fd2c)
- Bug 1219855, Part 3 - Fix variable shadowing in `OSXNotificationCenter::ShowAlert`. r=me (29e442fe45)
- Bug 1241377 - Part 1: Implement nsIFormPOSTActionChannel for the channel accepts form POST. r=mayhemer (f03e9dbece)
- Bug 1241377 - Part 2: Add test for nsIFormPOSTActionChannel. r=mayhemer (0a9e7aab1f)
- Bug 1207824: Add Telemetry for WebRTC call type, simultaneous tracks, and renegotiations r=bwc (38085ce155)
- Bug 1175609 - Bring onnegotiationneeded in line with spec. r=mt (398c03db6e)
- Bug 1209252 - Part 2: typo fix for compile issue. r=bustage on a CLOSED TREE (e1b8f43993)
- Bug 1221786: clear about:webrtc logs for private browsing sessions. r=jib (49615cc3c6)
- Bug 1232082 - add RTCRtpReceiver for each remote track. r=jesup (1231223782)
- Bug 1219711 - Remove fakeness from webrtc tests. r=jib (b421c55124)
- Bug 1232082 - add pc.ontrack and RTCTrackEvent r=jesup,smaug (f915ecc77c)
- Bug 1222127: Use the inner window to compute style. r=baku (a3ea812154)
- Bug 1209634 - Remove unused WindowTarget. r=past (1f2d218cb4)
- Bug 1209634 - Remove unused target.version. r=past (7ddf6cdfb1)
- Bug 1209634 - Reformat target.js to match ESLint rules. r=past (8fe93b4737)
- Bug 1168853 - Implement WorkerDebugger.isInitialized;r=khuey (318bd9516c)
- Bug 1150444 - Intermittent test_WorkerDebugger.isFrozen.xul;r=khuey (e787b9c935)
- Mark test_bug883784.jsm as a support file, no bug (c6c987138d)
- Bug 1178726 - Simplify how we deal with freezing/thawing workers;r=jlongster,khuey (88c7341f8f)
- Bug 1228382 - Expose an API to relate nsIWorkerDebugger to its nsIServiceWorkerInfo instance. r=ejpbruel (26ce55693f)

dom/html/HTMLInputElement.cpp

@@ -384,10 +384,10 @@ HTMLInputElement::nsFilePickerShownCallback::Done(int16_t aResult)
 
   // Collect new selected filenames
   nsTArray<RefPtr<File>> newFiles;
-  if (mode == static_cast<int16_t>(nsIFilePicker::modeOpenMultiple) ||
-      mode == static_cast<int16_t>(nsIFilePicker::modeGetFolder)) {
+  if (mode == static_cast<int16_t>(nsIFilePicker::modeOpenMultiple)) {
     nsCOMPtr<nsISimpleEnumerator> iter;
-    nsresult rv = mFilePicker->GetDomfiles(getter_AddRefs(iter));
+    nsresult rv =
+      mFilePicker->GetDomFileOrDirectoryEnumerator(getter_AddRefs(iter));
     NS_ENSURE_SUCCESS(rv, rv);
 
     if (!iter) {
@@ -407,9 +407,10 @@ HTMLInputElement::nsFilePickerShownCallback::Done(int16_t aResult)
       }
     }
   } else {
-    MOZ_ASSERT(mode == static_cast<int16_t>(nsIFilePicker::modeOpen));
+    MOZ_ASSERT(mode == static_cast<int16_t>(nsIFilePicker::modeOpen) ||
+               mode == static_cast<int16_t>(nsIFilePicker::modeGetFolder));
     nsCOMPtr<nsISupports> tmp;
-    nsresult rv = mFilePicker->GetDomfile(getter_AddRefs(tmp));
+    nsresult rv = mFilePicker->GetDomFileOrDirectory(getter_AddRefs(tmp));
     NS_ENSURE_SUCCESS(rv, rv);
 
     nsCOMPtr<nsIDOMBlob> blob = do_QueryInterface(tmp);
@@ -937,6 +938,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(HTMLInputElement,
   }
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFiles)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFileList)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFilesAndDirectoriesPromise)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(HTMLInputElement,
@@ -945,6 +947,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(HTMLInputElement,
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mControllers)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mFiles)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mFileList)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mFilesAndDirectoriesPromise)
   if (tmp->IsSingleLineTextControl(false)) {
     tmp->mInputData.mState->Unlink();
   }
@@ -2529,6 +2532,9 @@ HTMLInputElement::UpdateFileList()
     }
   }
 
+  // Make sure we (lazily) create a new Promise for GetFilesAndDirectories:
+  mFilesAndDirectoriesPromise = nullptr;
+
   return NS_OK;
 }
 
@@ -4831,6 +4837,9 @@ HTMLInputElement::ChooseDirectory(ErrorResult& aRv)
     aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
     return;
   }
+  // Script can call this method directly, so even though we don't show the
+  // "Pick Folder..." button on platforms that don't have a directory picker
+  // we have to redirect to the file picker here.
   InitFilePicker(
 #if defined(ANDROID) || defined(MOZ_B2G)
                  // No native directory picker - redirect to plain file picker
@@ -4841,30 +4850,13 @@ HTMLInputElement::ChooseDirectory(ErrorResult& aRv)
                  );
 }
 
-static already_AddRefed<OSFileSystem>
-MakeOrReuseFileSystem(const nsAString& aNewLocalRootPath,
-                      OSFileSystem* aFS,
-                      nsPIDOMWindow* aWindow)
-{
-  MOZ_ASSERT(aWindow);
-
-  RefPtr<OSFileSystem> fs;
-  if (aFS) {
-    const nsAString& prevLocalRootPath = aFS->GetLocalRootPath();
-    if (aNewLocalRootPath == prevLocalRootPath) {
-      fs = aFS;
-    }
-  }
-  if (!fs) {
-    fs = new OSFileSystem(aNewLocalRootPath);
-    fs->Init(aWindow);
-  }
-  return fs.forget();
-}
-
 already_AddRefed<Promise>
 HTMLInputElement::GetFilesAndDirectories(ErrorResult& aRv)
 {
+  if (mFilesAndDirectoriesPromise) {
+    return RefPtr<Promise>(mFilesAndDirectoriesPromise).forget();
+  }
+
   nsCOMPtr<nsIGlobalObject> global = OwnerDoc()->GetScopeObject();
   MOZ_ASSERT(global);
   if (!global) {
@@ -4885,8 +4877,6 @@ HTMLInputElement::GetFilesAndDirectories(ErrorResult& aRv)
     return p.forget();
   }
 
-  nsPIDOMWindow* window = OwnerDoc()->GetInnerWindow();
-  RefPtr<OSFileSystem> fs;
   for (uint32_t i = 0; i < filesAndDirs.Length(); ++i) {
     if (filesAndDirs[i]->IsDirectory()) {
 #if defined(ANDROID) || defined(MOZ_B2G)
@@ -4902,7 +4892,10 @@ HTMLInputElement::GetFilesAndDirectories(ErrorResult& aRv)
       }
       int32_t leafSeparatorIndex = path.RFind(FILE_PATH_SEPARATOR);
       nsDependentSubstring dirname = Substring(path, 0, leafSeparatorIndex);
-      fs = MakeOrReuseFileSystem(dirname, fs, window);
+
+      RefPtr<OSFileSystem> fs = new OSFileSystem(dirname);
+      fs->Init(OwnerDoc()->GetInnerWindow());
+
       nsAutoString dompath(NS_LITERAL_STRING(FILESYSTEM_DOM_PATH_SEPARATOR));
       dompath.Append(Substring(path, leafSeparatorIndex + 1));
       RefPtr<Directory> directory = new Directory(fs, dompath);
@@ -4919,6 +4912,11 @@ HTMLInputElement::GetFilesAndDirectories(ErrorResult& aRv)
 
   p->MaybeResolve(filesAndDirsSeq);
 
+  // Cache the Promise so that repeat getFilesAndDirectories() calls return
+  // the same Promise and array of File and Directory objects until the user
+  // picks different files/directories:
+  mFilesAndDirectoriesPromise = p;
+
   return p.forget();
 }
 
@@ -5549,10 +5547,10 @@ HTMLInputElement::SubmitNamesValues(nsFormSubmission* aFormSubmission)
     }
 
     if (files.IsEmpty()) {
-      // If no file was selected, pretend we had an empty file with an
-      // empty filename.
-      aFormSubmission->AddNameFilePair(name, nullptr);
-
+      RefPtr<BlobImpl> blobImpl =
+        new BlobImplEmptyFile(NS_LITERAL_STRING("application/octet-stream"));
+      RefPtr<File> file = File::Create(OwnerDoc()->GetInnerWindow(), blobImpl);
+      aFormSubmission->AddNameFilePair(name, file);
     }
 
     return NS_OK;