Do not send redundant selectionchange-events (decouple focus)

third_party/WebKit/Source/core/page/FocusController.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nuanti Ltd.
  *
  * 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
@@ skipping 1047 matching lines @@
   ScopedFocusNavigation scope =
       ScopedFocusNavigation::OwnedByShadowHost(shadow_host);
   return FindFocusableElementAcrossFocusScopes(kWebFocusTypeForward, scope);
 }
 
 static bool RelinquishesEditingFocus(const Element& element) {
   DCHECK(HasEditableStyle(element));
   return element.GetDocument().GetFrame() && RootEditableElement(element);
 }
 
-static void ClearSelectionIfNeeded(LocalFrame* old_focused_frame,
-                                   LocalFrame* new_focused_frame,
-                                   Element* new_focused_element) {
-  if (!old_focused_frame || !new_focused_frame)
-    return;
-
-  if (old_focused_frame->GetDocument() != new_focused_frame->GetDocument())
-    return;
-
-  FrameSelection& selection = old_focused_frame->Selection();
-  const SelectionInDOMTree& selection_in_dom_tree =
-      selection.GetSelectionInDOMTree();
-  if (selection_in_dom_tree.IsNone())
-    return;
-
-  Node* selection_start_node = selection_in_dom_tree.Base().AnchorNode();
-  if (selection_start_node == new_focused_element ||
-      selection_start_node->IsDescendantOf(new_focused_element))
-    return;
-
-  if (!EnclosingTextControl(selection_start_node))
-    return;
-
-  if (selection_start_node->IsInShadowTree() &&
-      selection_start_node->OwnerShadowHost() == new_focused_element)
-    return;
-
-  selection.Clear();
-}
-
 bool FocusController::SetFocusedElement(Element* element,
                                         Frame* new_focused_frame) {
   return SetFocusedElement(
       element, new_focused_frame,
       FocusParams(SelectionBehaviorOnFocus::kNone, kWebFocusTypeNone, nullptr));
 }
 
 bool FocusController::SetFocusedElement(Element* element,
                                         Frame* new_focused_frame,
                                         const FocusParams& params) {
@@ skipping 16 matching lines @@
   Document* new_document = nullptr;
   if (element)
     new_document = &element->GetDocument();
   else if (new_focused_frame && new_focused_frame->IsLocalFrame())
     new_document = ToLocalFrame(new_focused_frame)->GetDocument();
 
   if (new_document && old_document == new_document &&
       new_document->FocusedElement() == element)
     return true;
 
-  if (new_focused_frame && new_focused_frame->IsLocalFrame())
-    ClearSelectionIfNeeded(old_focused_frame, ToLocalFrame(new_focused_frame),
-                           element);
 
   if (old_document && old_document != new_document)
     old_document->ClearFocusedElement();
 
   if (new_focused_frame && !new_focused_frame->GetPage()) {
     SetFocusedFrame(nullptr);
     return false;
   }
   SetFocusedFrame(new_focused_frame);
 
@@ skipping 206 matching lines @@
   if (focus_candidate.is_offscreen_after_scrolling) {
     Node* container = focus_candidate.enclosing_scrollable_box;
     ScrollInDirection(container, type);
     return true;
   }
 
   // We found a new focus node, navigate to it.
   Element* element = ToElement(focus_candidate.focusable_node);
   DCHECK(element);
 
+  if (!element->IsTextControl() && !HasEditableStyle(*element->ToNode())) {
+    // To fulfill the expectation of spatial-navigation/snav-input.html
+    // we clear selection when spatnav moves focus away from a text-field.
+    FocusedFrame()->Selection().Clear();
+  }
   element->focus(FocusParams(SelectionBehaviorOnFocus::kReset, type, nullptr));
   return true;
 }
 
 bool FocusController::AdvanceFocusDirectionally(WebFocusType type) {
   // FIXME: Directional focus changes don't yet work with RemoteFrames.
   if (!FocusedOrMainFrame()->IsLocalFrame())
     return false;
   LocalFrame* cur_frame = ToLocalFrame(FocusedOrMainFrame());
   DCHECK(cur_frame);
@@ skipping 51 matching lines @@
     it->FocusedFrameChanged();
 }
 
 DEFINE_TRACE(FocusController) {
   visitor->Trace(page_);
   visitor->Trace(focused_frame_);
   visitor->Trace(focus_changed_observers_);
 }
 
 }  // namespace blink