Send an empty tooltip text when hovering over a different node

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

Index: third_party/WebKit/Source/core/page/ChromeClient.cpp
diff --git a/third_party/WebKit/Source/core/page/ChromeClient.cpp b/third_party/WebKit/Source/core/page/ChromeClient.cpp
index 0722386ff3d352bc587e7520346c1acf7da69b34..f8ad9928516cbc0766da5b48563bdf65f45f4f9f 100644
--- a/third_party/WebKit/Source/core/page/ChromeClient.cpp
+++ b/third_party/WebKit/Source/core/page/ChromeClient.cpp
@@ -38,6 +38,11 @@
 
 namespace blink {
 
+DEFINE_TRACE(ChromeClient) {
+  visitor->trace(m_lastMouseOverNode);
+  HostWindow::trace(visitor);
+}
+
 void ChromeClient::setWindowRectWithAdjustment(const IntRect& pendingRect,
                                                LocalFrame& frame) {
   IntRect screen = screenInfo().availableRect;
@@ -190,8 +195,20 @@ void ChromeClient::setToolTip(LocalFrame& frame, const HitTestResult& result) {
   if (m_lastToolTipPoint == result.hitTestLocation().point() &&
       m_lastToolTipText == toolTip)
     return;
+
+  // If a tooltip was displayed earlier, and mouse cursor moves over
+  // a different node with the same tooltip text, make sure the previous
+  // tooltip is unset, so that it does not get stuck positioned relative
+  // to the previous node).
+  // The ::setToolTip overload, which is be called down the road,
+  // ensures a new tooltip to be displayed with the new context.
+  if (result.innerNodeOrImageMapImage() != m_lastMouseOverNode &&
+      !m_lastToolTipText.isEmpty() && toolTip == m_lastToolTipText)
+    clearToolTip(frame);
+
   m_lastToolTipPoint = result.hitTestLocation().point();
   m_lastToolTipText = toolTip;
+  m_lastMouseOverNode = result.innerNodeOrImageMapImage();
   setToolTip(frame, toolTip, toolTipDirection);
 }