Only clear tooltip message on a user scroll or compositor scroll.

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 3798 matching lines @@
     m_pendingScrollDelta += scrollDelta;
 
   if (scrollTypeClearsFragmentAnchor(scrollType))
     clearFragmentAnchor();
   updateLayersAndCompositingAfterScrollIfNeeded();
 
   Document* document = m_frame->document();
   document->enqueueScrollEventForNode(document);
 
   m_frame->eventHandler().dispatchFakeMouseMoveEventSoon();
-  Page* page = frame().page();
-  if (page)
-    page->chromeClient().clearToolTip(*m_frame);
+  if (scrollType == UserScroll || scrollType == CompositorScroll) {
+    if (Page* page = frame().page())

[tdresser, 2017/01/03 13:56:32]

Moving the assignment to within the conditional makes this harder to read IMO.

+      page->chromeClient().clearToolTip(*m_frame);
+  }
 
   LayoutViewItem layoutViewItem = document->layoutViewItem();
   if (!layoutViewItem.isNull()) {
     if (layoutViewItem.usesCompositing())
       layoutViewItem.compositor()->frameViewDidScroll();
     layoutViewItem.clearHitTestCache();
   }
 
   m_didScrollTimer.startOneShot(resourcePriorityUpdateDelayAfterScroll,
                                 BLINK_FROM_HERE);
@@ skipping 1070 matching lines @@
        reason < MainThreadScrollingReason::kMainThreadScrollingReasonCount;
        ++reason) {
     if (m_mainThreadScrollingReasonsCounter[reason] > 0) {
       reasons |= 1 << (reason - 1);
     }
   }
   return reasons;
 }
 
 }  // namespace blink