Backed out changeset c9b71d1747ea (bug 1552814) for assertion failures on nsBaseDragService.cpp CLOSED TREE

--HG--
extra : rebase_source : 4a3e9922237c8638c9b2edd45cc2309094f3d352
extra : amend_source : 1629bf05b705065193ec1ee3e17086db3efd254e

dom/events/EventStateManager.cpp

@@ -1692,10 +1692,9 @@ void EventStateManager::StopTrackingDragGesture(bool aClearInChildProcesses) {
   mGestureDownFrameOwner = nullptr;
   mGestureDownDragStartData = nullptr;
 
-  // If a content process starts a drag but the mouse is released before the
-  // parent starts the actual drag, the content process will think a drag is
-  // still happening. Inform any child processes with active drags that the drag
-  // should be stopped.
+  // If a content process starts a drag but the mouse is released before the parent
+  // starts the actual drag, the content process will think a drag is still happening.
+  // Inform any child processes with active drags that the drag should be stopped.
   if (aClearInChildProcesses) {
     nsCOMPtr<nsIDragService> dragService =
         do_GetService("@mozilla.org/widget/dragservice;1");
@@ -1855,7 +1854,6 @@ void EventStateManager::GenerateDragGesture(nsPresContext* aPresContext,
   nsCOMPtr<nsIContent> eventContent, targetContent;
   nsCOMPtr<nsIPrincipal> principal;
   nsCOMPtr<nsIContentSecurityPolicy> csp;
-  bool allowEmptyDataTransfer = false;
   mCurrentTarget->GetContentForEvent(aEvent, getter_AddRefs(eventContent));
   if (eventContent) {
     // If the content is a text node in a password field, we shouldn't
@@ -1877,10 +1875,9 @@ void EventStateManager::GenerateDragGesture(nsPresContext* aPresContext,
       }
     }
     DetermineDragTargetAndDefaultData(
-        window, eventContent, dataTransfer, &allowEmptyDataTransfer,
-        getter_AddRefs(selection), getter_AddRefs(remoteDragStartData),
-        getter_AddRefs(targetContent), getter_AddRefs(principal),
-        getter_AddRefs(csp));
+        window, eventContent, dataTransfer, getter_AddRefs(selection),
+        getter_AddRefs(remoteDragStartData), getter_AddRefs(targetContent),
+        getter_AddRefs(principal), getter_AddRefs(csp));
   }
 
   // Stop tracking the drag gesture now. This should stop us from
@@ -1945,9 +1942,9 @@ void EventStateManager::GenerateDragGesture(nsPresContext* aPresContext,
   }
 
   if (status != nsEventStatus_eConsumeNoDefault) {
-    bool dragStarted = DoDefaultDragStart(
-        aPresContext, event, dataTransfer, allowEmptyDataTransfer,
-        targetContent, selection, remoteDragStartData, principal, csp);
+    bool dragStarted =
+        DoDefaultDragStart(aPresContext, event, dataTransfer, targetContent,
+                           selection, remoteDragStartData, principal, csp);
     if (dragStarted) {
       sActiveESM = nullptr;
       MaybeFirePointerCancel(aEvent);
@@ -1965,12 +1962,11 @@ void EventStateManager::GenerateDragGesture(nsPresContext* aPresContext,
 
 void EventStateManager::DetermineDragTargetAndDefaultData(
     nsPIDOMWindowOuter* aWindow, nsIContent* aSelectionTarget,
-    DataTransfer* aDataTransfer, bool* aAllowEmptyDataTransfer,
-    Selection** aSelection, RemoteDragStartData** aRemoteDragStartData,
-    nsIContent** aTargetNode, nsIPrincipal** aPrincipal,
-    nsIContentSecurityPolicy** aCsp) {
+    DataTransfer* aDataTransfer, Selection** aSelection,
+    RemoteDragStartData** aRemoteDragStartData, nsIContent** aTargetNode,
+    nsIPrincipal** aPrincipal, nsIContentSecurityPolicy** aCsp) {
   *aTargetNode = nullptr;
-  *aAllowEmptyDataTransfer = false;
+
   nsCOMPtr<nsIContent> dragDataNode;
 
   nsIContent* editingElement = aSelectionTarget->IsEditable()
@@ -1986,7 +1982,6 @@ void EventStateManager::DetermineDragTargetAndDefaultData(
       mGestureDownDragStartData->AddInitialDnDDataTo(aDataTransfer, aPrincipal,
                                                      aCsp);
       mGestureDownDragStartData.forget(aRemoteDragStartData);
-      *aAllowEmptyDataTransfer = true;
     }
   } else {
     mGestureDownDragStartData = nullptr;
@@ -2026,9 +2021,6 @@ void EventStateManager::DetermineDragTargetAndDefaultData(
     while (dragContent) {
       if (auto htmlElement = nsGenericHTMLElement::FromNode(dragContent)) {
         if (htmlElement->Draggable()) {
-          // We let draggable elements to trigger dnd even if there is no data
-          // in the DataTransfer.
-          *aAllowEmptyDataTransfer = true;
           break;
         }
       } else {
@@ -2065,8 +2057,7 @@ void EventStateManager::DetermineDragTargetAndDefaultData(
 
 bool EventStateManager::DoDefaultDragStart(
     nsPresContext* aPresContext, WidgetDragEvent* aDragEvent,
-    DataTransfer* aDataTransfer, bool aAllowEmptyDataTransfer,
-    nsIContent* aDragTarget, Selection* aSelection,
+    DataTransfer* aDataTransfer, nsIContent* aDragTarget, Selection* aSelection,
     RemoteDragStartData* aDragStartData, nsIPrincipal* aPrincipal,
     nsIContentSecurityPolicy* aCsp) {
   nsCOMPtr<nsIDragService> dragService =
@@ -2090,7 +2081,7 @@ bool EventStateManager::DoDefaultDragStart(
   if (aDataTransfer) {
     count = aDataTransfer->MozItemCount();
   }
-  if (!aAllowEmptyDataTransfer && !count) {
+  if (!count) {
     return false;
   }
 

dom/events/EventStateManager.h

@@ -1046,8 +1046,6 @@ class EventStateManager : public nsSupportsWeakReference, public nsIObserver {
    *
    * aSelectionTarget - target to check for selection
    * aDataTransfer - data transfer object that will contain the data to drag
-   * aAllowEmptyDataTransfer - [out] set to true, if dnd operation can be
-   *                           started even if DataTransfer is empty
    * aSelection - [out] set to the selection to be dragged
    * aTargetNode - [out] the draggable node, or null if there isn't one
    * aPrincipal - [out] set to the triggering principal of the drag, or null
@@ -1055,8 +1053,7 @@ class EventStateManager : public nsSupportsWeakReference, public nsIObserver {
    */
   void DetermineDragTargetAndDefaultData(
       nsPIDOMWindowOuter* aWindow, nsIContent* aSelectionTarget,
-      dom::DataTransfer* aDataTransfer, bool* aAllowEmptyDataTransfer,
-      dom::Selection** aSelection,
+      dom::DataTransfer* aDataTransfer, dom::Selection** aSelection,
       dom::RemoteDragStartData** aRemoteDragStartData, nsIContent** aTargetNode,
       nsIPrincipal** aPrincipal, nsIContentSecurityPolicy** aCsp);
 
@@ -1067,8 +1064,6 @@ class EventStateManager : public nsSupportsWeakReference, public nsIObserver {
    *
    * aDragEvent - the dragstart event
    * aDataTransfer - the data transfer that holds the data to be dragged
-   * aAllowEmptyDataTransfer - if true, dnd can be started even if there is no
-   *                           data to drag
    * aDragTarget - the target of the drag
    * aSelection - the selection to be dragged
    * aData - information pertaining to a drag started in a child process
@@ -1079,7 +1074,6 @@ class EventStateManager : public nsSupportsWeakReference, public nsIObserver {
   bool DoDefaultDragStart(nsPresContext* aPresContext,
                           WidgetDragEvent* aDragEvent,
                           dom::DataTransfer* aDataTransfer,
-                          bool aAllowEmptyDataTransfer,
                           nsIContent* aDragTarget, dom::Selection* aSelection,
                           dom::RemoteDragStartData* aDragStartData,
                           nsIPrincipal* aPrincipal,

widget/gtk/nsDragService.cpp

@@ -1244,9 +1244,6 @@ GtkTargetList* nsDragService::GetSourceList(void) {
       g_free(thisTarget);
     }
     g_free(targets);
-  } else {
-    // We need to create a dummy target list to be able initialize dnd.
-    targetList = gtk_target_list_new(nullptr, 0);
   }
   return targetList;
 }

widget/nsBaseDragService.cpp

@@ -46,7 +46,7 @@
 #include "mozilla/Unused.h"
 #include "nsFrameLoader.h"
 #include "BrowserParent.h"
-#include "nsIMutableArray.h"
+
 #include "gfxContext.h"
 #include "gfxPlatform.h"
 #include <algorithm>
@@ -253,28 +253,12 @@ nsBaseDragService::InvokeDragSession(
 
   uint32_t length = 0;
   mozilla::Unused << aTransferableArray->GetLength(&length);
-  if (!length) {
-    nsCOMPtr<nsIMutableArray> mutableArray =
-        do_QueryInterface(aTransferableArray);
-    if (mutableArray) {
-      // In order to be able trigger dnd, we need to have some transferable
-      // object.
-      nsCOMPtr<nsITransferable> trans =
-          do_CreateInstance("@mozilla.org/widget/transferable;1");
-      trans->Init(nullptr);
+  for (uint32_t i = 0; i < length; ++i) {
+    nsCOMPtr<nsITransferable> trans = do_QueryElementAt(aTransferableArray, i);
+    if (trans) {
+      // Set the requestingPrincipal on the transferable.
       trans->SetRequestingPrincipal(mSourceNode->NodePrincipal());
       trans->SetContentPolicyType(mContentPolicyType);
-      mutableArray->AppendElement(trans);
-    }
-  } else {
-    for (uint32_t i = 0; i < length; ++i) {
-      nsCOMPtr<nsITransferable> trans =
-          do_QueryElementAt(aTransferableArray, i);
-      if (trans) {
-        // Set the requestingPrincipal on the transferable.
-        trans->SetRequestingPrincipal(mSourceNode->NodePrincipal());
-        trans->SetContentPolicyType(mContentPolicyType);
-      }
     }
   }
 
@@ -880,8 +864,9 @@ bool nsBaseDragService::MaybeAddChildProcess(
 bool nsBaseDragService::RemoveAllChildProcesses() {
   for (uint32_t c = 0; c < mChildProcesses.Length(); c++) {
     mozilla::Unused << mChildProcesses[c]->SendEndDragSession(
-        true, false, LayoutDeviceIntPoint(), 0);
+      true, false, LayoutDeviceIntPoint(), 0);
   }
   mChildProcesses.Clear();
   return true;
 }
+