Don't clear selection on focus change except for text form control element

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 659 matching lines @@
 
     if (Node* mousePressNode = newFocusedFrame->eventHandler().mousePressNode()) {
         if (mousePressNode->renderer() && !mousePressNode->canStartSelection()) {
             // Don't clear the selection for contentEditable elements, but do
             // clear it for input and textarea. See bug 38696.
             if (!enclosingTextFormControl(selection.start()))
                 return;
         }
     }
 
-    selection.clear();
+    if (newFocusedNode && (newFocusedNode->hasEditableStyle()

[leviw_travelin_and_unemployed, 2014/07/29 19:56:40]

Is it actually possible for newFocusedNode to be null here?

[yosin_UTC9, 2014/07/30 00:48:07]

Yes.  EventHandler::handleMouseFocus() calls
FocusController::setFocusedElement() with nullptr.
Here is excerpt from EventHandler.cpp:

 // We call setFocusedElement even with !element in order to blur
 // current focus element when a link is clicked; this is expected by
 // some sites that rely on onChange handlers running from form
 // fields before the button click is processed.
 if (!page->focusController().setFocusedElement(0, m_frame))

[leviw_travelin_and_unemployed, 2014/07/30 19:19:19]

I know we can have no newFocusedNode, I'm just not convinced we'd get this far
in the function before early returning.

Anyhow, lgtm.

+        || (newFocusedNode->isElementNode() && isHTMLTextFormControlElement(toElement(newFocusedNode))))) {
+        selection.clear();
+        return;
+    }
 }
 
 bool FocusController::setFocusedElement(Element* element, PassRefPtr<Frame> newFocusedFrame, FocusType type)
 {
     RefPtr<LocalFrame> oldFocusedFrame = toLocalFrame(focusedFrame());
     RefPtrWillBeRawPtr<Document> oldDocument = oldFocusedFrame ? oldFocusedFrame->document() : 0;
 
     Element* oldFocusedElement = oldDocument ? oldDocument->focusedElement() : 0;
     if (element && oldFocusedElement == element)
         return true;
@@ skipping 239 matching lines @@
         startingRect = nodeRectInAbsoluteCoordinates(container, true /* ignore border */);
         container = scrollableEnclosingBoxOrParentFrameForNodeInDirection(type, container);
         if (container && container->isDocumentNode())
             toDocument(container)->updateLayoutIgnorePendingStylesheets();
     } while (!consumed && container);
 
     return consumed;
 }
 
 } // namespace blink