Document::updateHoverActiveState only cancel hover and active state when hitting native scrollbar

third_party/WebKit/Source/web/tests/WebFrameTest.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 10473 matching lines @@
   Document* document = webView->mainFrameImpl()->frame()->document();
   Element* aTag = document->getElementById("a");
 
   // Ensure hittest has scrollbar and link
   HitTestResult hitTestResult =
       webView->coreHitTestResultAt(WebPoint(18, aTag->offsetTop()));
 
   EXPECT_TRUE(hitTestResult.URLElement());
   EXPECT_TRUE(hitTestResult.innerElement());
   EXPECT_TRUE(hitTestResult.scrollbar());
+  EXPECT_FALSE(hitTestResult.scrollbar()->isCustomScrollbar());
 
   // Mouse over link. Mouse cursor should be hand.
   PlatformMouseEvent mouseMoveOverLinkEvent(
       IntPoint(aTag->offsetLeft(), aTag->offsetTop()),
       IntPoint(aTag->offsetLeft(), aTag->offsetTop()),
       WebPointerProperties::Button::NoButton, PlatformEvent::MouseMoved, 0,
       PlatformEvent::NoModifiers, WTF::monotonicallyIncreasingTime());
   document->frame()->eventHandler().handleMouseMoveEvent(
       mouseMoveOverLinkEvent);
 
@@ skipping 47 matching lines @@
       Cursor::Type::Hand,
       document->frame()->chromeClient().lastSetCursorForTesting().getType());
 
   document->frame()->eventHandler().handleMousePressEvent(mousePressEvent);
 
   EXPECT_TRUE(document->activeHoverElement());
   EXPECT_TRUE(document->hoverNode());
 
   document->frame()->eventHandler().handleMouseReleaseEvent(MouseReleaseEvent);
 }
+
+// Makes sure that mouse hover over an custom scrollbar doesn't change the
+// activate elements.
+TEST_F(WebFrameTest, MouseOverCustomScrollbar) {
+  registerMockedHttpURLLoad("custom-scrollbar-hover.html");
+  FrameTestHelpers::WebViewHelper webViewHelper;
+  WebViewImpl* webView = webViewHelper.initializeAndLoad(
+      m_baseURL + "custom-scrollbar-hover.html");
+
+  webViewHelper.resize(WebSize(200, 200));
+
+  webView->updateAllLifecyclePhases();
+
+  Document* document = toLocalFrame(webView->page()->mainFrame())->document();
+
+  Element* scrollbarDiv = document->getElementById("scrollbar");
+  EXPECT_TRUE(scrollbarDiv);
+
+  // Ensure hittest only has DIV
+  HitTestResult hitTestResult = webView->coreHitTestResultAt(WebPoint(1, 1));
+
+  EXPECT_TRUE(hitTestResult.innerElement());
+  EXPECT_FALSE(hitTestResult.scrollbar());
+
+  // Mouse over DIV
+  PlatformMouseEvent mouseMoveOverDiv(
+      IntPoint(1, 1), IntPoint(1, 1), WebPointerProperties::Button::NoButton,
+      PlatformEvent::MouseMoved, 0, PlatformEvent::NoModifiers,
+      WTF::monotonicallyIncreasingTime());
+  document->frame()->eventHandler().handleMouseMoveEvent(mouseMoveOverDiv);
+
+  // DIV :hover
+  EXPECT_EQ(document->hoverNode(), scrollbarDiv);
+
+  // Ensure hittest has DIV and scrollbar
+  hitTestResult = webView->coreHitTestResultAt(WebPoint(175, 175));
+
+  EXPECT_TRUE(hitTestResult.innerElement());
+  EXPECT_TRUE(hitTestResult.scrollbar());
+  EXPECT_TRUE(hitTestResult.scrollbar()->isCustomScrollbar());
+
+  // Mouse over DIV
+  PlatformMouseEvent mouseMoveOverDivAndScrollbar(
+      IntPoint(175, 175), IntPoint(175, 175),
+      WebPointerProperties::Button::NoButton, PlatformEvent::MouseMoved, 0,
+      PlatformEvent::NoModifiers, WTF::monotonicallyIncreasingTime());
+  document->frame()->eventHandler().handleMouseMoveEvent(
+      mouseMoveOverDivAndScrollbar);
+
+  // Custom not change the DIV :hover
+  EXPECT_EQ(document->hoverNode(), scrollbarDiv);

[bokan, 2016/11/23 17:09:51]

Can you also check that the scrollbar thumb has the :hover state. I'm not sure
how to do this but there's a few avenues to try:

A custom scrollbar is represented by a LayoutScrollbar which has a LayoutPart
for the thumb. You should be able to get the ComputedStyle for that. Not sure
how you check for hover state there but code search might be helpful.

LayoutTheme has isHovered helper. Not sure if it works for custom scrollbars
though.

Maybe Scrollbar::hoveredPart is simple enough?

+}
+
 static void disableCompositing(WebSettings* settings) {
   settings->setAcceleratedCompositingEnabled(false);
   settings->setPreferCompositingToLCDTextEnabled(false);
 }
 
 // Make sure overlay scrollbars on non-composited scrollers fade out and set
 // the hidden bit as needed.
 TEST_F(WebFrameTest, TestNonCompositedOverlayScrollbarsFade) {
   FrameTestHelpers::WebViewHelper webViewHelper;
   WebViewImpl* webViewImpl = webViewHelper.initialize(
@@ skipping 78 matching lines @@
   Frame* mainFrame = webViewHelper.webView()->mainFrameImpl()->frame();
   HashSet<AtomicString> names;
   for (Frame* frame = mainFrame->tree().firstChild(); frame;
        frame = frame->tree().traverseNext()) {
     EXPECT_TRUE(names.add(frame->tree().uniqueName()).isNewEntry);
   }
   EXPECT_EQ(10u, names.size());
 }
 
 }  // namespace blink