Bug 1789974: Fix shortcut creation when pinning to taskbar r=bytesized

In the recent refactor of this (https://bugzilla.mozilla.org/show_bug.cgi?id=1782295) I managed to break our ability to create shortcuts if they don't already existed. This was caused by two things:
1) An errant `NS_SUCCEEDED` call remained after the call it was checking moved elsewhere (oops)
2) The taskbar pinning code was not updated to set the shortcut file path (required after the refactor).

This patches fixes both of those issues. Note that all the directory service interaction is done on the main thread, because the actual function doing the work is on a background thread, and the directory service does not work there.

Differential Revision: https://phabricator.services.mozilla.com/D156993

browser/components/shell/nsWindowsShellService.cpp

@@ -1403,12 +1403,10 @@ static nsresult PinCurrentAppToTaskbarWin10(bool aCheckOnly,
   }
 }
 
-static nsresult PinCurrentAppToTaskbarImpl(bool aCheckOnly,
-                                           bool aPrivateBrowsing,
-                                           const nsAString& aAppUserModelId,
-                                           const nsAString& aShortcutName,
-                                           nsIFile* aShortcutsLogDir,
-                                           nsIFile* greDir) {
+static nsresult PinCurrentAppToTaskbarImpl(
+    bool aCheckOnly, bool aPrivateBrowsing, const nsAString& aAppUserModelId,
+    const nsAString& aShortcutName, nsIFile* aShortcutsLogDir, nsIFile* aGreDir,
+    nsIFile* aProgramsDir) {
   MOZ_DIAGNOSTIC_ASSERT(
       !NS_IsMainThread(),
       "PinCurrentAppToTaskbarImpl should be called off main thread only");
@@ -1429,11 +1427,8 @@ static nsresult PinCurrentAppToTaskbarImpl(bool aCheckOnly,
 
     nsAutoString linkName(aShortcutName);
 
-    nsCOMPtr<nsIFile> exeFile(greDir);
+    nsCOMPtr<nsIFile> exeFile(aGreDir);
     if (aPrivateBrowsing) {
-      if (!NS_SUCCEEDED(rv)) {
-        return NS_ERROR_FAILURE;
-      }
       nsAutoString pbExeStr(PRIVATE_BROWSING_BINARY);
       nsresult rv = exeFile->Append(pbExeStr);
       if (!NS_SUCCEEDED(rv)) {
@@ -1451,12 +1446,16 @@ static nsresult PinCurrentAppToTaskbarImpl(bool aCheckOnly,
       }
     }
 
+    nsCOMPtr<nsIFile> shortcutFile(aProgramsDir);
+    shortcutFile->Append(aShortcutName);
+
     nsTArray<nsString> arguments;
     rv = CreateShortcutImpl(exeFile, arguments, aShortcutName, exeFile,
                             // Icon indexes are defined as Resource IDs, but
                             // CreateShortcutImpl needs an index.
                             IDI_APPICON - 1, aAppUserModelId, FOLDERID_Programs,
-                            linkName, shortcutPath, aShortcutsLogDir);
+                            linkName, shortcutFile->NativePath(),
+                            aShortcutsLogDir);
     if (!NS_SUCCEEDED(rv)) {
       return NS_ERROR_FILE_NOT_FOUND;
     }
@@ -1525,11 +1524,13 @@ static nsresult PinCurrentAppToTaskbarAsyncImpl(bool aCheckOnly,
     shortcutName.AppendLiteral(MOZ_APP_DISPLAYNAME ".lnk");
   }
 
-  nsCOMPtr<nsIFile> greDir, updRoot, shortcutsLogDir;
+  nsCOMPtr<nsIFile> greDir, updRoot, programsDir, shortcutsLogDir;
   nsresult nsrv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(greDir));
   NS_ENSURE_SUCCESS(nsrv, nsrv);
   nsrv = NS_GetSpecialDirectory(XRE_UPDATE_ROOT_DIR, getter_AddRefs(updRoot));
   NS_ENSURE_SUCCESS(nsrv, nsrv);
+  rv = NS_GetSpecialDirectory(NS_WIN_PROGRAMS_DIR, getter_AddRefs(programsDir));
+  NS_ENSURE_SUCCESS(nsrv, nsrv);
   nsrv = updRoot->GetParent(getter_AddRefs(shortcutsLogDir));
   NS_ENSURE_SUCCESS(nsrv, nsrv);
 
@@ -1540,14 +1541,15 @@ static nsresult PinCurrentAppToTaskbarAsyncImpl(bool aCheckOnly,
       NS_NewRunnableFunction(
           "CheckPinCurrentAppToTaskbarAsync",
           [aCheckOnly, aPrivateBrowsing, shortcutName, aumid = nsString{aumid},
-           shortcutsLogDir, greDir, promiseHolder = std::move(promiseHolder)] {
+           shortcutsLogDir, greDir, programsDir,
+           promiseHolder = std::move(promiseHolder)] {
             nsresult rv = NS_ERROR_FAILURE;
             HRESULT hr = CoInitialize(nullptr);
 
             if (SUCCEEDED(hr)) {
               rv = PinCurrentAppToTaskbarImpl(
                   aCheckOnly, aPrivateBrowsing, aumid, shortcutName,
-                  shortcutsLogDir.get(), greDir.get());
+                  shortcutsLogDir.get(), greDir.get(), programsDir.get());
               CoUninitialize();
             }