Bug 728652, null check return value of MozGetDataAt, r=ehsan

editor/libeditor/base/tests/test_dragdrop.html

@@ -117,6 +117,12 @@ function doTest()
 //  synthesizeDrop(text, textarea, [[{type: "text/plain", data: "Somewhat Longer Text"}]], "copy");
 //  is(textarea.value, "Somewhat Longer Text", "Drag text/plain onto textarea");
 
+  // -------- Test dragging special text type of text/plain to contenteditable
+
+  selection.selectAllChildren(text);
+  synthesizeDrop(text, input, [[{type: "text/x-moz-text-internal", data: "Some Special Text"}]], "copy");
+  is(input.value, "Some Plain Text", "Drag text/x-moz-text-internal onto input");
+
   // -------- Test dragging regular text of text/plain to contenteditable
 
   selection.selectAllChildren(text);

editor/libeditor/text/nsPlaintextDataTransfer.cpp

@@ -169,12 +169,16 @@ nsresult nsPlaintextEditor::InsertFromDataTransfer(nsIDOMDataTransfer *aDataTran
   nsCOMPtr<nsIVariant> data;
   aDataTransfer->MozGetDataAt(NS_LITERAL_STRING("text/plain"), aIndex,
                               getter_AddRefs(data));
-  nsAutoString insertText;
-  data->GetAsAString(insertText);
-  nsContentUtils::PlatformToDOMLineBreaks(insertText);
+  if (data) {
+    nsAutoString insertText;
+    data->GetAsAString(insertText);
+    nsContentUtils::PlatformToDOMLineBreaks(insertText);
 
-  nsAutoEditBatch beginBatching(this);
-  return InsertTextAt(insertText, aDestinationNode, aDestOffset, aDoDeleteSelection);
+    nsAutoEditBatch beginBatching(this);
+    return InsertTextAt(insertText, aDestinationNode, aDestOffset, aDoDeleteSelection);
+  }
+
+  return NS_OK;
 }
 
 nsresult nsPlaintextEditor::InsertFromDrop(nsIDOMEvent* aDropEvent)