Send an empty tooltip text when hovering over a different node

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

Index: third_party/WebKit/Source/core/page/ChromeClient.h
diff --git a/third_party/WebKit/Source/core/page/ChromeClient.h b/third_party/WebKit/Source/core/page/ChromeClient.h
index 46510033a27f038f44c13c8de13248865c16f894..45a79229a1c527d2029f36c54ed3b7374051387b 100644
--- a/third_party/WebKit/Source/core/page/ChromeClient.h
+++ b/third_party/WebKit/Source/core/page/ChromeClient.h
@@ -337,6 +337,8 @@ class CORE_EXPORT ChromeClient : public HostWindow {
 
   virtual void installSupplements(LocalFrame&) {}
 
+  DECLARE_TRACE();
+
  protected:
   ~ChromeClient() override {}
 
@@ -358,6 +360,7 @@ class CORE_EXPORT ChromeClient : public HostWindow {
                                          const String& message);
   void setToolTip(LocalFrame&, const HitTestResult&);
 
+  WeakMember<Node> m_lastMouseOverNode;

[Stephen Chennney, 2017/01/03 20:38:25]

Does this really need to be a weak pointer, rather than a raw pointer? You only
ever use it for comparing the pointer value, never to access, so it seems to me
that a raw pointer would work.

   LayoutPoint m_lastToolTipPoint;
   String m_lastToolTipText;