--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -5392,18 +5392,17 @@ nsContentUtils::SetDataTransferInEvent(W
     initialDataTransfer =
       new DataTransfer(aDragEvent->mTarget, aDragEvent->mMessage, true, -1);
 
     // now set it in the drag session so we don't need to create it again
     dragSession->SetDataTransfer(initialDataTransfer);
   }
 
   bool isCrossDomainSubFrameDrop = false;
-  if (aDragEvent->mMessage == eDrop ||
-      aDragEvent->mMessage == eLegacyDragDrop) {
+  if (aDragEvent->mMessage == eDrop) {
     isCrossDomainSubFrameDrop = CheckForSubFrameDrop(dragSession, aDragEvent);
   }
 
   // each event should use a clone of the original dataTransfer.
   initialDataTransfer->Clone(aDragEvent->mTarget, aDragEvent->mMessage,
                              aDragEvent->mUserCancelled,
                              isCrossDomainSubFrameDrop,
                              getter_AddRefs(aDragEvent->mDataTransfer));
@@ -5417,17 +5416,16 @@ nsContentUtils::SetDataTransferInEvent(W
   if (aDragEvent->mMessage == eDragEnter || aDragEvent->mMessage == eDragOver) {
     uint32_t action, effectAllowed;
     dragSession->GetDragAction(&action);
     aDragEvent->mDataTransfer->GetEffectAllowedInt(&effectAllowed);
     aDragEvent->mDataTransfer->SetDropEffectInt(
                                  FilterDropEffect(action, effectAllowed));
   }
   else if (aDragEvent->mMessage == eDrop ||
-           aDragEvent->mMessage == eLegacyDragDrop ||
            aDragEvent->mMessage == eDragEnd) {
     // For the drop and dragend events, set the drop effect based on the
     // last value that the dropEffect had. This will have been set in
     // EventStateManager::PostHandleEvent for the last dragenter or
     // dragover event.
     uint32_t dropEffect;
     initialDataTransfer->GetDropEffectInt(&dropEffect);
     aDragEvent->mDataTransfer->SetDropEffectInt(dropEffect);

--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -323,17 +323,16 @@ GK_ATOM(DOMAttrModified, "DOMAttrModifie
 GK_ATOM(DOMCharacterDataModified, "DOMCharacterDataModified")
 GK_ATOM(DOMNodeInserted, "DOMNodeInserted")
 GK_ATOM(DOMNodeInsertedIntoDocument, "DOMNodeInsertedIntoDocument")
 GK_ATOM(DOMNodeRemoved, "DOMNodeRemoved")
 GK_ATOM(DOMNodeRemovedFromDocument, "DOMNodeRemovedFromDocument")
 GK_ATOM(DOMSubtreeModified, "DOMSubtreeModified")
 GK_ATOM(double_, "double")
 GK_ATOM(drag, "drag")
-GK_ATOM(dragdrop, "dragdrop")
 GK_ATOM(dragend, "dragend")
 GK_ATOM(dragenter, "dragenter")
 GK_ATOM(dragevent, "dragevent")
 GK_ATOM(dragexit, "dragexit")
 GK_ATOM(draggable, "draggable")
 GK_ATOM(dragging, "dragging")
 GK_ATOM(dragleave, "dragleave")
 GK_ATOM(dragover, "dragover")

--- a/dom/events/DataTransfer.cpp
+++ b/dom/events/DataTransfer.cpp
@@ -611,18 +611,17 @@ DataTransfer::GetDataAtInternal(const ns
 
   // Check if the caller is allowed to access the drag data. Callers with
   // chrome privileges can always read the data. During the
   // drop event, allow retrieving the data except in the case where the
   // source of the drag is in a child frame of the caller. In that case,
   // we only allow access to data of the same principal. During other events,
   // only allow access to the data with the same principal.
   bool checkFormatItemPrincipal = mIsCrossDomainSubFrameDrop ||
-      (mEventMessage != eDrop && mEventMessage != eLegacyDragDrop &&
-       mEventMessage != ePaste);
+      (mEventMessage != eDrop && mEventMessage != ePaste);
   MOZ_ASSERT(aSubjectPrincipal);
 
   RefPtr<DataTransferItem> item = mItems->MozItemByTypeAt(format, aIndex);
   if (!item) {
     // The index exists but there's no data for the specified format, in this
     // case we just return undefined
     return NS_OK;
   }

--- a/dom/events/EventNameList.h
+++ b/dom/events/EventNameList.h
@@ -769,20 +769,16 @@ NON_IDL_EVENT(broadcast,
 NON_IDL_EVENT(commandupdate,
               eXULCommandUpdate,
               EventNameType_XUL,
               eBasicEventClass)
 NON_IDL_EVENT(dragexit,
               eDragExit,
               EventNameType_XUL,
               eDragEventClass)
-NON_IDL_EVENT(dragdrop,
-              eLegacyDragDrop,
-              EventNameType_XUL,
-              eDragEventClass)
 NON_IDL_EVENT(overflow,
               eScrollPortOverflow,
               EventNameType_XUL,
               eBasicEventClass)
 NON_IDL_EVENT(underflow,
               eScrollPortUnderflow,
               EventNameType_XUL,
               eBasicEventClass)

--- a/dom/plugins/base/nsPluginInstanceOwner.cpp
+++ b/dom/plugins/base/nsPluginInstanceOwner.cpp
@@ -2901,17 +2901,16 @@ nsPluginInstanceOwner::Destroy()
   content->RemoveEventListener(NS_LITERAL_STRING("click"), this, false);
   content->RemoveEventListener(NS_LITERAL_STRING("dblclick"), this, false);
   content->RemoveEventListener(NS_LITERAL_STRING("mouseover"), this, false);
   content->RemoveEventListener(NS_LITERAL_STRING("mouseout"), this, false);
   content->RemoveEventListener(NS_LITERAL_STRING("keypress"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("keydown"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("keyup"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("drop"), this, true);
-  content->RemoveEventListener(NS_LITERAL_STRING("dragdrop"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("drag"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("dragenter"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("dragover"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("dragleave"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("dragexit"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("dragstart"), this, true);
   content->RemoveEventListener(NS_LITERAL_STRING("dragend"), this, true);
   content->RemoveSystemEventListener(NS_LITERAL_STRING("compositionstart"),
@@ -3300,17 +3299,16 @@ nsresult nsPluginInstanceOwner::Init(nsI
   aContent->AddEventListener(NS_LITERAL_STRING("mouseover"), this, false,
                              false);
   aContent->AddEventListener(NS_LITERAL_STRING("mouseout"), this, false,
                              false);
   aContent->AddEventListener(NS_LITERAL_STRING("keypress"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("keydown"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("keyup"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("drop"), this, true);
-  aContent->AddEventListener(NS_LITERAL_STRING("dragdrop"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("drag"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("dragenter"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("dragover"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("dragleave"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("dragexit"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("dragstart"), this, true);
   aContent->AddEventListener(NS_LITERAL_STRING("dragend"), this, true);
   aContent->AddSystemEventListener(NS_LITERAL_STRING("compositionstart"),

--- a/widget/EventMessageList.h
+++ b/widget/EventMessageList.h
@@ -126,17 +126,16 @@ NS_EVENT_MESSAGE(eFormInvalid)
 
 //Need separate focus/blur notifications for non-native widgets
 NS_EVENT_MESSAGE(eFocus)
 NS_EVENT_MESSAGE(eBlur)
 
 NS_EVENT_MESSAGE(eDragEnter)
 NS_EVENT_MESSAGE(eDragOver)
 NS_EVENT_MESSAGE(eDragExit)
-NS_EVENT_MESSAGE(eLegacyDragDrop)
 NS_EVENT_MESSAGE(eDrag)
 NS_EVENT_MESSAGE(eDragEnd)
 NS_EVENT_MESSAGE(eDragStart)
 NS_EVENT_MESSAGE(eDrop)
 NS_EVENT_MESSAGE(eDragLeave)
 NS_EVENT_MESSAGE_FIRST_LAST(eDragDropEvent, eDragEnter, eDragLeave)
 
 // XUL specific events

--- a/widget/WidgetEventImpl.cpp
+++ b/widget/WidgetEventImpl.cpp
@@ -208,17 +208,16 @@ WidgetEvent::HasMouseEventMessage() cons
 
 bool
 WidgetEvent::HasDragEventMessage() const
 {
   switch (mMessage) {
     case eDragEnter:
     case eDragOver:
     case eDragExit:
-    case eLegacyDragDrop:
     case eDrag:
     case eDragEnd:
     case eDragStart:
     case eDrop:
     case eDragLeave:
       return true;
     default:
       return false;