Change hover element to scrollbar's parent when hit test contains scrollbar

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

Index: third_party/WebKit/Source/web/tests/WebFrameTest.cpp
diff --git a/third_party/WebKit/Source/web/tests/WebFrameTest.cpp b/third_party/WebKit/Source/web/tests/WebFrameTest.cpp
index d123a03ceffb17247de312433aaba890b5e7b4b9..9952bf9943cf6d20a9da217b88e860e6963f4a73 100644
--- a/third_party/WebKit/Source/web/tests/WebFrameTest.cpp
+++ b/third_party/WebKit/Source/web/tests/WebFrameTest.cpp
@@ -10833,7 +10833,8 @@ TEST_F(WebFrameTest, MouseOverDifferntNodeClearsTooltip) {
 }
 
 // Makes sure that mouse hover over an overlay scrollbar doesn't activate
-// elements below unless the scrollbar is faded out.
+// elements below(except the Element that owns the scrollbar) unless the
+// scrollbar is faded out.
 TEST_F(WebFrameTest, MouseOverLinkAndOverlayScrollbar) {
   FrameTestHelpers::WebViewHelper webViewHelper;
   webViewHelper.initialize(true, nullptr, nullptr, nullptr,
@@ -10995,6 +10996,92 @@ TEST_F(WebFrameTest, MouseOverCustomScrollbar) {
   EXPECT_EQ(hitTestResult.scrollbar()->hoveredPart(), ScrollbarPart::ThumbPart);
 }
 
+// Makes sure that mouse hover over a scrollbar also hover the element owns the
+// scrollbar.
+TEST_F(WebFrameTest, MouseOverScrollbarAndParentElement) {
+  registerMockedHttpURLLoad("scrollbar-and-element-hover.html");
+  FrameTestHelpers::WebViewHelper webViewHelper;
+  WebViewImpl* webView = webViewHelper.initializeAndLoad(
+      m_baseURL + "scrollbar-and-element-hover.html", true);
+
+  webViewHelper.resize(WebSize(200, 200));
+
+  webView->updateAllLifecyclePhases();
+
+  WebLocalFrameImpl* frame = webViewHelper.webView()->mainFrameImpl();
+  Document* document = toLocalFrame(webView->page()->mainFrame())->document();
+
+  Element* parentDiv = document->getElementById("parent");
+  EXPECT_TRUE(parentDiv);
+
+  ScrollableArea* scrollableArea =
+      toLayoutBox(parentDiv->layoutObject())->getScrollableArea();
+
+  EXPECT_TRUE(scrollableArea->verticalScrollbar());
+
+  // Ensure hittest only has DIV.
+  HitTestResult hitTestResult = webView->coreHitTestResultAt(WebPoint(1, 1));
+
+  EXPECT_TRUE(hitTestResult.innerElement());
+  EXPECT_FALSE(hitTestResult.scrollbar());
+
+  // Mouse over DIV.
+  WebMouseEvent mouseMoveOverDiv(
+      WebInputEvent::MouseMove, WebFloatPoint(1, 1), WebFloatPoint(1, 1),
+      WebPointerProperties::Button::NoButton, 0, WebInputEvent::NoModifiers,
+      TimeTicks::Now().InSeconds());
+  mouseMoveOverDiv.setFrameScale(1);
+  document->frame()->eventHandler().handleMouseMoveEvent(
+      mouseMoveOverDiv, Vector<WebMouseEvent>());
+
+  // DIV :hover.
+  EXPECT_EQ(document->hoverNode(), parentDiv);
+
+  // Ensure hittest has DIV and scrollbar.
+  hitTestResult = webView->coreHitTestResultAt(WebPoint(175, 5));
+
+  EXPECT_TRUE(hitTestResult.innerElement());
+  EXPECT_TRUE(hitTestResult.scrollbar());
+  EXPECT_FALSE(hitTestResult.scrollbar()->isCustomScrollbar());
+  EXPECT_TRUE(hitTestResult.scrollbar()->enabled());
+
+  // Mouse over scrollbar.
+  WebMouseEvent mouseMoveOverDivAndScrollbar(
+      WebInputEvent::MouseMove, WebFloatPoint(175, 5), WebFloatPoint(175, 5),
+      WebPointerProperties::Button::NoButton, 0, WebInputEvent::NoModifiers,
+      TimeTicks::Now().InSeconds());
+  mouseMoveOverDivAndScrollbar.setFrameScale(1);
+  document->frame()->eventHandler().handleMouseMoveEvent(
+      mouseMoveOverDivAndScrollbar, Vector<WebMouseEvent>());
+
+  // Not change the DIV :hover.
+  EXPECT_EQ(document->hoverNode(), parentDiv);
+
+  // Disable the Scrollbar by remove the childDiv.
+  frame->executeScript(
+      WebScriptSource("var parent = document.getElementById('parent');"
+                      "var child = document.getElementById('child');"
+                      "parent.removeChild(child);"));
+  webView->updateAllLifecyclePhases();
+
+  scrollableArea = toLayoutBox(parentDiv->layoutObject())->getScrollableArea();

[bokan, 2017/02/03 01:51:22]

Do you need this? I wouldn't expect us to create a new ScrollableArea.

[chaopeng, 2017/02/03 17:00:30]

I just tried to get scrollbar with this. Removed.

+
+  EXPECT_FALSE(scrollableArea->verticalScrollbar());

[chaopeng, 2017/02/03 01:12:05]

I tried to get the disabled scrollbar here. But I got no scrollbar.

[bokan, 2017/02/03 01:51:22]

Interesting. I would expect us to have created a disabled scrollbar. Check that
the Element's clientWidth shrunk by the scrollbar width.

I expect that in here:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/paint/Pai...

The LayoutBox::hasOverflowClip returns false in scrollsOverflowY so we don't
create a scrollbar. That begs the question, how do we paint the
scrollbar...anyway, you can confirm but if the clientWidth shrinks that's enough
for me.

+
+  // Ensure hittest has DIV and no scrollbar.
+  hitTestResult = webView->coreHitTestResultAt(WebPoint(175, 5));
+
+  EXPECT_TRUE(hitTestResult.innerElement());
+  EXPECT_FALSE(hitTestResult.scrollbar());
+
+  // Mouse over disabled scrollbar.
+  document->frame()->eventHandler().handleMouseMoveEvent(
+      mouseMoveOverDivAndScrollbar, Vector<WebMouseEvent>());
+
+  // Not change the DIV :hover.
+  EXPECT_EQ(document->hoverNode(), parentDiv);
+}
+
 TEST_F(WebFrameTest, MouseReleaseUpdatesScrollbarHoveredPart) {
   registerMockedHttpURLLoad("custom-scrollbar-hover.html");
   FrameTestHelpers::WebViewHelper webViewHelper;