Do not show a tooltip same as the previous one.

third_party/WebKit/Source/core/page/ChromeClient.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple, Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #ifndef ChromeClient_h
 #define ChromeClient_h
 
+#include "base/gtest_prod_util.h"
 #include "core/CoreExport.h"
 #include "core/dom/AXObjectCache.h"
 #include "core/frame/ConsoleTypes.h"
 #include "core/inspector/ConsoleAPITypes.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/NavigationPolicy.h"
 #include "core/style/ComputedStyleConstants.h"
 #include "platform/Cursor.h"
 #include "platform/HostWindow.h"
 #include "platform/PopupMenu.h"
@@ skipping 113 matching lines @@
 
     virtual void dispatchViewportPropertiesDidChange(const ViewportDescription&) const { }
 
     virtual void contentsSizeChanged(LocalFrame*, const IntSize&) const = 0;
     virtual void pageScaleFactorChanged() const { }
     virtual float clampPageScaleFactorToLimits(float scale) const { return scale; }
     virtual void layoutUpdated(LocalFrame*) const { }
 
     void mouseDidMoveOverElement(const HitTestResult&);
     virtual void setToolTip(const String&, TextDirection) = 0;
+    void clearToolTip();
 
     void print(LocalFrame*);
 
     virtual void annotatedRegionsChanged() = 0;
 
     virtual PassOwnPtrWillBeRawPtr<ColorChooser> openColorChooser(LocalFrame*, ColorChooserClient*, const Color&) = 0;
 
     // This function is used for:
     //  - Mandatory date/time choosers if !ENABLE(INPUT_MULTIPLE_FIELDS_UI)
     //  - Date/time choosers for types for which LayoutTheme::supportsCalendarPicker
@@ skipping 95 matching lines @@
     virtual void setWindowRect(const IntRect&) = 0;
     virtual bool openBeforeUnloadConfirmPanelDelegate(LocalFrame*, const String& message, bool isReload) = 0;
     virtual bool openJavaScriptAlertDelegate(LocalFrame*, const String&) = 0;
     virtual bool openJavaScriptConfirmDelegate(LocalFrame*, const String&) = 0;
     virtual bool openJavaScriptPromptDelegate(LocalFrame*, const String& message, const String& defaultValue, String& result) = 0;
     virtual void printDelegate(LocalFrame*) = 0;
 
 private:
     bool canOpenModalIfDuringPageDismissal(Frame* mainFrame, DialogType, const String& message);
     void setToolTip(const HitTestResult&);
+
+    LayoutPoint m_lastToolTipPoint;
+    String m_lastToolTipText;
+
+    FRIEND_TEST_ALL_PREFIXES(ChromeClientTest, SetToolTipFlood);
 };
 
 } // namespace blink
 
 #endif // ChromeClient_h