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

Source/core/page/FocusController.cpp

Index: Source/core/page/FocusController.cpp
diff --git a/Source/core/page/FocusController.cpp b/Source/core/page/FocusController.cpp
index bdf43b6cf4144a2b28f93de3553567f2e3ace5f1..761539a93665ef2825b98dabeaca881eef8313b6 100644
--- a/Source/core/page/FocusController.cpp
+++ b/Source/core/page/FocusController.cpp
@@ -677,7 +677,11 @@ static void clearSelectionIfNeeded(LocalFrame* oldFocusedFrame, LocalFrame* newF
         }
     }
 
-    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)