Bug 1143934 - Disallow mozSetFileNameArray in content processes. r=ehsan

Summary of rationale: it never entirely worked, in that the File objects
it created would cause form submission to fail, and the longer-term plan
for content-process system-principal scripts is to remove APIs that allow
direct filesystem access.

dom/html/HTMLInputElement.cpp

@@ -1831,7 +1831,7 @@ HTMLInputElement::SetValue(const nsAString& aValue, ErrorResult& aRv)
       }
       Sequence<nsString> list;
       list.AppendElement(aValue);
-      MozSetFileNameArray(list);
+      MozSetFileNameArray(list, aRv);
       return;
     }
     else {
@@ -2352,8 +2352,13 @@ HTMLInputElement::MozSetFileArray(const Sequence<OwningNonNull<File>>& aFiles)
 }
 
 void
-HTMLInputElement::MozSetFileNameArray(const Sequence< nsString >& aFileNames)
+HTMLInputElement::MozSetFileNameArray(const Sequence< nsString >& aFileNames, ErrorResult& aRv)
 {
+  if (XRE_GetProcessType() == GeckoProcessType_Content) {
+    aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+    return;
+  }
+
   nsTArray<nsRefPtr<File>> files;
   for (uint32_t i = 0; i < aFileNames.Length(); ++i) {
     nsCOMPtr<nsIFile> file;
@@ -2397,8 +2402,9 @@ HTMLInputElement::MozSetFileNameArray(const char16_t** aFileNames, uint32_t aLen
     list.AppendElement(nsDependentString(aFileNames[i]));
   }
 
-  MozSetFileNameArray(list);
-  return NS_OK;
+  ErrorResult rv;
+  MozSetFileNameArray(list, rv);
+  return rv.ErrorCode();
 }
 
 bool
@@ -2445,8 +2451,9 @@ HTMLInputElement::SetUserInput(const nsAString& aValue)
   {
     Sequence<nsString> list;
     list.AppendElement(aValue);
-    MozSetFileNameArray(list);
-    return NS_OK;
+    ErrorResult rv;
+    MozSetFileNameArray(list, rv);
+    return rv.ErrorCode();
   } else {
     nsresult rv = SetValueInternal(aValue, true, true);
     NS_ENSURE_SUCCESS(rv, rv);

dom/html/HTMLInputElement.h

@@ -715,7 +715,7 @@ public:
 
   void MozGetFileNameArray(nsTArray< nsString >& aFileNames);
 
-  void MozSetFileNameArray(const Sequence< nsString >& aFileNames);
+  void MozSetFileNameArray(const Sequence< nsString >& aFileNames, ErrorResult& aRv);
   void MozSetFileArray(const Sequence<OwningNonNull<File>>& aFiles);
 
   HTMLInputElement* GetOwnerNumberControl();

dom/webidl/HTMLInputElement.webidl

@@ -151,7 +151,7 @@ partial interface HTMLInputElement {
   [ChromeOnly]
   sequence<DOMString> mozGetFileNameArray();
 
-  [ChromeOnly]
+  [ChromeOnly, Throws]
   void mozSetFileNameArray(sequence<DOMString> fileNames);
 
   [ChromeOnly]