Do not show a tooltip same as the previous one.

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

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/page/ChromeClient.h"
+
+#include "core/dom/Document.h"
+#include "core/layout/HitTestResult.h"
+#include "core/loader/EmptyClients.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+
+namespace {
+
+class ChromeClientToolTipLogger : public EmptyChromeClient {
+public:
+    void setToolTip(const String& text, TextDirection) override
+    {
+        m_toolTipForLastSetToolTip = text;
+    }
+
+    String toolTipForLastSetToolTip() const { return m_toolTipForLastSetToolTip; }
+    void clearToolTipForLastSetToolTip() { m_toolTipForLastSetToolTip = String(); }
+
+private:
+    String m_toolTipForLastSetToolTip;
+};
+
+} // anonymous namespace
+
+class ChromeClientTest : public testing::Test {
+};
+
+TEST_F(ChromeClientTest, SetToolTipFlood)
+{
+    ChromeClientToolTipLogger logger;
+    ChromeClient* client = &logger;
+    HitTestResult result(HitTestRequest(HitTestRequest::Move), LayoutPoint(10, 20));
+    RefPtrWillBeRawPtr<Document> doc = Document::create();
+    RefPtrWillBeRawPtr<Element> element = HTMLElement::create(HTMLNames::divTag, *doc);
+    element->setAttribute(HTMLNames::titleAttr, "tooltip");
+    result.setInnerNode(element.get());
+
+    client->setToolTip(result);
+    EXPECT_EQ("tooltip", logger.toolTipForLastSetToolTip());
+
+    // seToolTip(HitTestResult) again in the same condition.
+    logger.clearToolTipForLastSetToolTip();
+    client->setToolTip(result);
+    // setToolTip(String,TextDirection) should not be called.
+    EXPECT_EQ(String(), logger.toolTipForLastSetToolTip());
+
+    // Cancel the tooltip, and setToolTip(HitTestResult) again.
+    client->clearToolTip();
+    logger.clearToolTipForLastSetToolTip();
+    client->setToolTip(result);
+    // setToolTip(String,TextDirection) should not be called.
+    EXPECT_EQ(String(), logger.toolTipForLastSetToolTip());
+
+    logger.clearToolTipForLastSetToolTip();
+    element->setAttribute(HTMLNames::titleAttr, "updated");
+    client->setToolTip(result);
+    // setToolTip(String,TextDirection) should be called because tooltip string
+    // is different from the last one.
+    EXPECT_EQ("updated", logger.toolTipForLastSetToolTip());
+}
+
+} // namespace blink