Do not send redundant selectionchange-events (decouple focus)

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

 /*
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 356 matching lines @@
   const Node* result = nullptr;
   for (const Node* n = &node; n && hasEditableStyle(*n); n = n->parentNode()) {
     if (n->isElementNode())
       result = n;
     if (node.document().body() == n)
       break;
   }
   return toElement(const_cast<Node*>(result));
 }
 
+bool selectionHasFocus(const LocalFrame& frame,

[yosin_UTC9, 2017/03/22 05:07:59]

Let's take Document from selection instead of extra parameter |frame|.

[hugoh_UTC2, 2017/03/22 07:50:33]

SelectionTemplate currently keeps Document private but sure, we can make it
public.

[yosin_UTC9, 2017/03/22 07:53:19]

You can get Document by Position, e.g. selection.base().document()

[hugoh_UTC2, 2017/03/22 08:32:38]

Done. See PS25.

+                       const SelectionInFlatTree& selection) {
+  const Element* focus = frame.document()->focusedElement();
+  if (!focus) {
+    // No focused element means document root has focus.
+    focus = frame.document()->documentElement();
+  }
+
+  const Node* const nodeWhereSelectionStarts =
+      selection.base().computeContainerNode();
+  const Node* const nodeWhereSelectionEnds =
+      selection.extent().computeContainerNode();
+
+  return focus->containsIncludingHostElements(*nodeWhereSelectionStarts) ||
+         focus->containsIncludingHostElements(*nodeWhereSelectionEnds);
+}
+
 ContainerNode* highestEditableRoot(
     const Position& position,
     Element* (*rootEditableElementOf)(const Position&),
     bool (*hasEditableStyle)(const Node&)) {
   if (position.isNull())
     return 0;
 
   ContainerNode* highestRoot = rootEditableElementOf(position);
   if (!highestRoot)
     return 0;
@@ skipping 1786 matching lines @@
         return InputType::DeleteWordBackward;
       if (granularity == LineBoundary)
         return InputType::DeleteLineBackward;
       return InputType::DeleteContentBackward;
     default:
       return InputType::None;
   }
 }
 
 }  // namespace blink