Bug 1119126 - Send updateposition after reflow when selection is collapsed. r=roc

dom/browser-element/BrowserElementChildPreload.js

@@ -638,6 +638,8 @@ BrowserElementChild.prototype = {
     // We clear selectionStateChangedTarget if selection carets are invisible.
     if (e.visible && !isCollapsed) {
       this._selectionStateChangedTarget = e.target;
+    } else if (canPaste && isCollapsed) {
+      this._selectionStateChangedTarget = e.target;
     } else {
       this._selectionStateChangedTarget = null;
     }
@@ -1144,6 +1146,7 @@ BrowserElementChild.prototype = {
 
   _recvDoCommand: function(data) {
     if (this._isCommandEnabled(data.json.command)) {
+      this._selectionStateChangedTarget = null;
       docShell.doCommand(COMMAND_MAP[data.json.command]);
     }
   },

layout/base/SelectionCarets.cpp

@@ -1220,6 +1220,12 @@ SelectionCarets::ScrollPositionChanged()
                                            SelectionState::Updateposition);
       }
     }
+  } else {
+    nsRefPtr<dom::Selection> selection = GetSelection();
+    if (selection && selection->RangeCount() && selection->IsCollapsed()) {
+      DispatchSelectionStateChangedEvent(selection,
+                                         SelectionState::Updateposition);
+    }
   }
 }
 
@@ -1317,6 +1323,12 @@ SelectionCarets::Reflow(DOMHighResTimeStamp aStart, DOMHighResTimeStamp aEnd)
       DispatchSelectionStateChangedEvent(GetSelection(),
                                          SelectionState::Updateposition);
     }
+  } else {
+    nsRefPtr<dom::Selection> selection = GetSelection();
+    if (selection && selection->RangeCount() && selection->IsCollapsed()) {
+      DispatchSelectionStateChangedEvent(selection,
+                                         SelectionState::Updateposition);
+    }
   }
   return NS_OK;
 }