[InputEvent] Support |deleteByDrag| and |insertFromDrop|

third_party/WebKit/Source/core/editing/Editor.cpp

Index: third_party/WebKit/Source/core/editing/Editor.cpp
diff --git a/third_party/WebKit/Source/core/editing/Editor.cpp b/third_party/WebKit/Source/core/editing/Editor.cpp
index 477e1de0f71b071d8c669549dc110d78e6a2b5d5..012f8ad4085056924c7b4e1a66de326d9ce00202 100644
--- a/third_party/WebKit/Source/core/editing/Editor.cpp
+++ b/third_party/WebKit/Source/core/editing/Editor.cpp
@@ -102,19 +102,23 @@ void dispatchInputEvent(Element* target, InputEvent::InputType inputType, const
 {
     if (!RuntimeEnabledFeatures::inputEventEnabled())
         return;
-    if (!target)
+    if (!target || !target->isConnected())

[yosin_UTC9, 2016/09/08 04:34:40]

One more.
Could you make |disaptchInputEvent()| to take |const Document&
originateDocument| and check or DCEHCK |target->ownerDocument() ==
originateDocument|
to catch source and destination still in document starting drag-and-drop.

[chongz, 2016/09/08 22:37:50]

I've added check for |ownerDocument()| but I don't really understand why...
  1. Drag&drop could happen from one iframe to another, so I assume their
document are not necessarily to be the same.
  2. If we want to make sure |ownerDocument()| for one target doesn't change
during the drag&drop, we should record |originalDocument| before 'beforeinput'
and check here, but |Editor::appliedEditing()| doesn't seem to have that
information?
  3. If we just want to make sure 'input' handler for |startRoot| doesn't do
anything bad, we already have |dispatchScopedEvent()| which only dispatch events
when safe, or did I misunderstood something?

Thanks!

[chongz, 2016/09/13 17:17:12]

dtapuska@ I'm not sure if I understood the issue correctly, can you take a look
please? thanks!

[dtapuska, 2016/09/13 17:27:50]

Ya this change seems odd to me. The old code use to ensure that only one
inputEvent was dispatched. That is why it was checking the endRoot didn't
matched the startRoot. But with the type of the event changing both events need
to be dispatched. And I find passing the originateDocument into the
dispatchInputEvent confusing. If you wanted to assert that the endRoot's
document matched the startRoot's document then you should do it on line 116. 

[yosin_UTC9, 2016/09/14 01:57:37]

I changed mind, we should verify source and target aren't removed from originate
document.

* Event order: (See [1] [2])
  1. 'drop'
  2. 'beforeinput' InputType=|deleteByDrag|
Verify source and target aren't removed.

  3. 'beforeinput' InputType=|insertFromDrop|
Verify source and target arent' removed.
  4. (DOM update)
Both source and target are modified, we don't care source and target anymore.
But, we don't dispatch events for source and target if they aren't connected.
  5. 'input' InputType=|deleteByDrag|
  6. 'input' InputType=|insertFromDrop|
  7. 'dragend'

Given that, |Editor| should observe nodeWillBeRemoved and nodeChildrenRemoved()
to stop drag-and-drop process when either source or target removed.
Is it better to introduce DragAndDropEventDispatcher class and make |Editor| to
hold it during drag-and-drop?

         return;
-    // TODO(chongz): Pass appreciate |ranges| after it's defined on spec.
-    // http://w3c.github.io/editing/input-events.html#dom-inputevent-inputtype
     InputEvent* inputEvent = InputEvent::createInput(inputType, data, isComposing, nullptr);
     target->dispatchScopedEvent(inputEvent);
 }
 
 void dispatchInputEventEditableContentChanged(Element* startRoot, Element* endRoot, InputEvent::InputType inputType, const String& data, InputEvent::EventIsComposing isComposing)
 {
-    if (startRoot)
-        dispatchInputEvent(startRoot, inputType, data, isComposing);
-    if (endRoot && endRoot != startRoot)
+    if (inputType == InputEvent::InputType::MoveByDragDrop) {
+        // Drag&Drop will be combined into one |MoveSelectionCommand|, we need to split it into |DeleteByDrag| and |InsertFromDrop|.
+        dispatchInputEvent(startRoot, InputEvent::InputType::DeleteByDrag, data, isComposing);
+        dispatchInputEvent(endRoot, InputEvent::InputType::InsertFromDrop, data, isComposing);
+        return;
+    }
+
+    dispatchInputEvent(startRoot, inputType, data, isComposing);
+    if (endRoot != startRoot)
         dispatchInputEvent(endRoot, inputType, data, isComposing);
 }
 
@@ -560,7 +564,7 @@ void Editor::replaceSelectionAfterDragging(DocumentFragment* fragment, bool smar
     if (plainText)
         options |= ReplaceSelectionCommand::MatchStyle;
     DCHECK(frame().document());
-    ReplaceSelectionCommand::create(*frame().document(), fragment, options, InputEvent::InputType::Drag)->apply();
+    ReplaceSelectionCommand::create(*frame().document(), fragment, options, InputEvent::InputType::InsertFromDrop)->apply();
 }
 
 void Editor::moveSelectionAfterDragging(DocumentFragment* fragment, const Position& pos, bool smartInsert, bool smartDelete)