Implement overlay scrollbar fade out for non-composited scrollers.

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 2c1b85b20f51d313b5aa95ee4414c0f06d68cbc3..637306d061388c1c9d8a29824d64487e89cfa9e6 100644
--- a/third_party/WebKit/Source/web/tests/WebFrameTest.cpp
+++ b/third_party/WebKit/Source/web/tests/WebFrameTest.cpp
@@ -86,6 +86,7 @@
 #include "platform/geometry/FloatRect.h"
 #include "platform/network/ResourceError.h"
 #include "platform/scroll/ScrollbarTheme.h"
+#include "platform/scroll/ScrollbarThemeOverlayMock.h"
 #include "platform/testing/RuntimeEnabledFeaturesTestHelpers.h"
 #include "platform/testing/URLTestHelpers.h"
 #include "platform/testing/UnitTestHelpers.h"
@@ -10429,26 +10430,118 @@ TEST_F(WebFrameTest, HidingScrollbarsOnScrollableAreaDisablesScrollbars) {
   ASSERT_TRUE(frameView->verticalScrollbar());
 
   EXPECT_FALSE(frameView->scrollbarsHidden());
-  EXPECT_TRUE(frameView->horizontalScrollbar()->enabled());
-  EXPECT_TRUE(frameView->verticalScrollbar()->enabled());
+  EXPECT_TRUE(
+      frameView->horizontalScrollbar()->shouldParticipateInHitTesting());
+  EXPECT_TRUE(frameView->verticalScrollbar()->shouldParticipateInHitTesting());
 
   EXPECT_FALSE(scrollerArea->scrollbarsHidden());
-  EXPECT_TRUE(scrollerArea->horizontalScrollbar()->enabled());
-  EXPECT_TRUE(scrollerArea->verticalScrollbar()->enabled());
+  EXPECT_TRUE(
+      scrollerArea->horizontalScrollbar()->shouldParticipateInHitTesting());
+  EXPECT_TRUE(
+      scrollerArea->verticalScrollbar()->shouldParticipateInHitTesting());
 
   frameView->setScrollbarsHidden(true);
-  EXPECT_FALSE(frameView->horizontalScrollbar()->enabled());
-  EXPECT_FALSE(frameView->verticalScrollbar()->enabled());
+  EXPECT_FALSE(
+      frameView->horizontalScrollbar()->shouldParticipateInHitTesting());
+  EXPECT_FALSE(frameView->verticalScrollbar()->shouldParticipateInHitTesting());
   frameView->setScrollbarsHidden(false);
-  EXPECT_TRUE(frameView->horizontalScrollbar()->enabled());
-  EXPECT_TRUE(frameView->verticalScrollbar()->enabled());
+  EXPECT_TRUE(
+      frameView->horizontalScrollbar()->shouldParticipateInHitTesting());
+  EXPECT_TRUE(frameView->verticalScrollbar()->shouldParticipateInHitTesting());
 
   scrollerArea->setScrollbarsHidden(true);
-  EXPECT_FALSE(scrollerArea->horizontalScrollbar()->enabled());
-  EXPECT_FALSE(scrollerArea->verticalScrollbar()->enabled());
+  EXPECT_FALSE(
+      scrollerArea->horizontalScrollbar()->shouldParticipateInHitTesting());
+  EXPECT_FALSE(
+      scrollerArea->verticalScrollbar()->shouldParticipateInHitTesting());
   scrollerArea->setScrollbarsHidden(false);
-  EXPECT_TRUE(scrollerArea->horizontalScrollbar()->enabled());
-  EXPECT_TRUE(scrollerArea->verticalScrollbar()->enabled());
+  EXPECT_TRUE(
+      scrollerArea->horizontalScrollbar()->shouldParticipateInHitTesting());
+  EXPECT_TRUE(
+      scrollerArea->verticalScrollbar()->shouldParticipateInHitTesting());
+}
+
+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(
+      true, nullptr, nullptr, nullptr, &disableCompositing);
+
+  constexpr double kMockOverlayFadeOutDelayMs = 5.0;
+
+  ScrollbarTheme& theme = ScrollbarTheme::theme();
+  // This test relies on mock overlay scrollbars.
+  ASSERT_TRUE(theme.isMockTheme());
+  ASSERT_TRUE(theme.usesOverlayScrollbars());
+  ScrollbarThemeOverlayMock& mockOverlayTheme =
+      (ScrollbarThemeOverlayMock&)theme;
+  mockOverlayTheme.setOverlayScrollbarFadeOutDelay(kMockOverlayFadeOutDelayMs /
+                                                   1000.0);
+
+  webViewImpl->resizeWithBrowserControls(WebSize(640, 480), 0, false);
+
+  WebURL baseURL = URLTestHelpers::toKURL("http://example.com/");
+  FrameTestHelpers::loadHTMLString(webViewImpl->mainFrame(),
+                                   "<!DOCTYPE html>"
+                                   "<style>"
+                                   "  #space {"
+                                   "    width: 1000px;"
+                                   "    height: 1000px;"
+                                   "  }"
+                                   "  #container {"
+                                   "    width: 200px;"
+                                   "    height: 200px;"
+                                   "    overflow: scroll;"
+                                   "  }"
+                                   "  div { height:1000px; width: 200px; }"
+                                   "</style>"
+                                   "<div id='container'>"
+                                   "  <div id='space'></div>"
+                                   "</div>",
+                                   baseURL);
+  webViewImpl->updateAllLifecyclePhases();
+
+  WebLocalFrameImpl* frame = webViewHelper.webView()->mainFrameImpl();
+  Document* document =
+      toLocalFrame(webViewImpl->page()->mainFrame())->document();
+  Element* container = document->getElementById("container");
+  ScrollableArea* scrollableArea =
+      toLayoutBox(container->layoutObject())->getScrollableArea();
+
+  EXPECT_FALSE(scrollableArea->scrollbarsHidden());
+  testing::runDelayedTasks(kMockOverlayFadeOutDelayMs);
+  EXPECT_TRUE(scrollableArea->scrollbarsHidden());
+
+  scrollableArea->setScrollOffset(ScrollOffset(10, 10), ProgrammaticScroll,
+                                  ScrollBehaviorInstant);
+
+  EXPECT_FALSE(scrollableArea->scrollbarsHidden());
+  testing::runDelayedTasks(kMockOverlayFadeOutDelayMs);
+  EXPECT_TRUE(scrollableArea->scrollbarsHidden());
+
+  frame->executeScript(WebScriptSource(
+      "document.getElementById('space').style.height = '500px';"));
+  frame->view()->updateAllLifecyclePhases();
+
+  EXPECT_FALSE(scrollableArea->scrollbarsHidden());
+  testing::runDelayedTasks(kMockOverlayFadeOutDelayMs);
+  EXPECT_TRUE(scrollableArea->scrollbarsHidden());
+
+  frame->executeScript(WebScriptSource(
+      "document.getElementById('container').style.height = '300px';"));
+  frame->view()->updateAllLifecyclePhases();
+
+  EXPECT_FALSE(scrollableArea->scrollbarsHidden());
+  testing::runDelayedTasks(kMockOverlayFadeOutDelayMs);
+  EXPECT_TRUE(scrollableArea->scrollbarsHidden());
+
+  mockOverlayTheme.setOverlayScrollbarFadeOutDelay(0.0);
 }
 
 TEST_F(WebFrameTest, UniqueNames) {