Fix main thread top controls scrolling to mirror CC.

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

 /*
  * Copyright (C) 2015 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 140 matching lines @@
 #define MAYBE(test) DISABLED_##test
 #else
 #define MAYBE(test) test
 #endif
 
 // Scrolling down should hide top controls.
 TEST_F(TopControlsTest, MAYBE(HideOnScrollDown))
 {
     WebViewImpl* webView = initialize();
     // initialize top controls to be shown.
-    webView->setTopControlsHeight(50.f, true);
+    webView->resizeWithTopControls(webView->size(), 50.f, true);
     webView->topControls().setShownRatio(1);
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollBegin));
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
 
     // Top controls should be scrolled partially and page should not scroll.
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, -25.f));
     EXPECT_FLOAT_EQ(25.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 0), frame()->view()->scrollPosition());
 
     // Top controls should consume 25px and become hidden. Excess scroll should be consumed by the page.
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, -40.f));
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 15), frame()->view()->scrollPosition());
 
     // Only page should consume scroll
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, -20.f));
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 35), frame()->view()->scrollPosition());
 }
 
 // Scrolling up should show top controls.
 TEST_F(TopControlsTest, MAYBE(ShowOnScrollUp))
 {
     WebViewImpl* webView = initialize();
     // initialize top controls to be hidden.
-    webView->setTopControlsHeight(50.f, false);
+    webView->resizeWithTopControls(webView->size(), 50.f, false);
     webView->topControls().setShownRatio(0);
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollBegin));
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, 10.f));
     EXPECT_FLOAT_EQ(10.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 0), frame()->view()->scrollPosition());
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, 50.f));
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 0), frame()->view()->scrollPosition());
 }
 
 // Scrolling up after previous scroll downs should cause top controls to be
 // shown only after all previously scrolled down amount is compensated.
 TEST_F(TopControlsTest, MAYBE(ScrollDownThenUp))
 {
     WebViewImpl* webView = initialize();
     // initialize top controls to be shown and position page at 100px.
-    webView->setTopControlsHeight(50.f, true);
+    webView->resizeWithTopControls(webView->size(), 50.f, true);
     webView->topControls().setShownRatio(1);
     frame()->view()->getScrollableArea()->setScrollPosition(IntPoint(0, 100), ProgrammaticScroll);
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollBegin));
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
 
     // Scroll down to completely hide top controls. Excess deltaY (100px) should be consumed by the page.
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, -150.f));
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 200), frame()->view()->scrollPosition());
@@ skipping 17 matching lines @@
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 50), frame()->view()->scrollPosition());
 }
 
 // Scrolling down should always cause visible top controls to start hiding even
 // if we have been scrolling up previously.
 TEST_F(TopControlsTest, MAYBE(ScrollUpThenDown))
 {
     WebViewImpl* webView = initialize();
     // initialize top controls to be hidden and position page at 100px.
-    webView->setTopControlsHeight(50.f, false);
+    webView->resizeWithTopControls(webView->size(), 50.f, false);
     webView->topControls().setShownRatio(0);
     frame()->view()->getScrollableArea()->setScrollPosition(IntPoint(0, 100), ProgrammaticScroll);
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollBegin));
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
 
     // Scroll up to completely show top controls. Excess deltaY (50px) should be consumed by the page.
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, 100.f));
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 50), frame()->view()->scrollPosition());
 
     // Scroll down and ensure only top controls is scrolled
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, -40.f));
     EXPECT_FLOAT_EQ(10.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 50), frame()->view()->scrollPosition());
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, -60.f));
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 100), frame()->view()->scrollPosition());
 }
 
 // Top controls should not consume horizontal scroll.
 TEST_F(TopControlsTest, MAYBE(HorizontalScroll))
 {
     WebViewImpl* webView = initialize();
     // initialize top controls to be shown.
-    webView->setTopControlsHeight(50.f, true);
+    webView->resizeWithTopControls(webView->size(), 50.f, true);
     webView->topControls().setShownRatio(1);
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollBegin));
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
 
     // Top controls should not consume horizontal scroll.
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, -110.f, -100.f));
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(110, 50), frame()->view()->scrollPosition());
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, -40.f, 0));
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(150, 50), frame()->view()->scrollPosition());
 }
 
 // Page scale should not impact top controls scrolling
 TEST_F(TopControlsTest, MAYBE(PageScaleHasNoImpact))
 {
     WebViewImpl* webView = initialize();
     webViewImpl()->setDefaultPageScaleLimits(0.25f, 5);
     webView->setPageScaleFactor(2.0);
 
     // Initialize top controls to be shown.
-    webView->setTopControlsHeight(50.f, true);
+    webView->resizeWithTopControls(webView->size(), 50.f, true);
     webView->topControls().setShownRatio(1);
 
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollBegin));
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
 
     // Top controls should be scrolled partially and page should not scroll.
     webView->handleInputEvent(generateEvent(WebInputEvent::GestureScrollUpdate, 0, -20.f));
     EXPECT_FLOAT_EQ(30.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 0), frame()->view()->getScrollableArea()->scrollPositionDouble());
 
@@ skipping 25 matching lines @@
 // floating-point number. Make sure that if the top controls aren't fully
 // scrolled, scrollBy doesn't return any excess delta. i.e. There should be no
 // slippage between the content and top controls.
 TEST_F(TopControlsTest, MAYBE(FloatingPointSlippage))
 {
     WebViewImpl* webView = initialize();
     webViewImpl()->setDefaultPageScaleLimits(0.25f, 5);
     webView->setPageScaleFactor(2.0);
 
     // Initialize top controls to be shown.
-    webView->setTopControlsHeight(50.f, true);
+    webView->resizeWithTopControls(webView->size(), 50.f, true);
     webView->topControls().setShownRatio(1);
 
     webView->topControls().scrollBegin();
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
 
     // This will result in a 20px scroll to the top controls so the show ratio
     // will be 30/50 == 0.6 which is not representible in a float. Make sure
     // that scroll still consumes the whole delta.
     FloatSize remainingDelta = webView->topControls().scrollBy(FloatSize(0, 10));
     EXPECT_EQ(0, remainingDelta.height());
 }
 
 // Scrollable subregions should scroll before top controls
 TEST_F(TopControlsTest, MAYBE(ScrollableSubregionScrollFirst))
 {
     WebViewImpl* webView = initialize("overflow-scrolling.html");
-    webView->setTopControlsHeight(50.f, true);
+    webView->resizeWithTopControls(webView->size(), 50.f, true);
     webView->topControls().setShownRatio(1);
     frame()->view()->getScrollableArea()->setScrollPosition(IntPoint(0, 50), ProgrammaticScroll);
 
     // Test scroll down
     // Scroll down should scroll the overflow div first but top controls and main frame should not scroll.
     verticalScroll(-800.f);
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 50), frame()->view()->scrollPosition());
 
     // Continued scroll down should start hiding top controls but main frame should not scroll.
@@ skipping 21 matching lines @@
     verticalScroll(40.f);
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 50), frame()->view()->scrollPosition());
 }
 
 
 // Scrollable iframes should scroll before top controls
 TEST_F(TopControlsTest, MAYBE(ScrollableIframeScrollFirst))
 {
     WebViewImpl* webView = initialize("iframe-scrolling.html");
-    webView->setTopControlsHeight(50.f, true);
+    webView->resizeWithTopControls(webView->size(), 50.f, true);
     webView->topControls().setShownRatio(1);
     frame()->view()->getScrollableArea()->setScrollPosition(IntPoint(0, 50), ProgrammaticScroll);
 
     // Test scroll down
     // Scroll down should scroll the iframe first but top controls and main frame should not scroll.
     verticalScroll(-800.f);
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 50), frame()->view()->scrollPosition());
 
     // Continued scroll down should start hiding top controls but main frame should not scroll.
@@ skipping 20 matching lines @@
     // Continued scroll down up scroll up the main frame
     verticalScroll(40.f);
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 50), frame()->view()->scrollPosition());
 }
 
 // Top controls visibility should remain consistent when height is changed.
 TEST_F(TopControlsTest, MAYBE(HeightChangeMaintainsVisibility))
 {
     WebViewImpl* webView = initialize();
-    webView->setTopControlsHeight(20.f, false);
+    webView->resizeWithTopControls(webView->size(), 20.f, false);
     webView->topControls().setShownRatio(0);
 
-    webView->setTopControlsHeight(20.f, false);
+    webView->resizeWithTopControls(webView->size(), 20.f, false);
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
 
-    webView->setTopControlsHeight(40.f, false);
+    webView->resizeWithTopControls(webView->size(), 40.f, false);
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
 
     // Scroll up to show top controls.
     verticalScroll(40.f);
     EXPECT_FLOAT_EQ(40.f, webView->topControls().contentOffset());
 
     // Changing height of a fully shown top controls should correctly adjust content offset
-    webView->setTopControlsHeight(30.f, false);
+    webView->resizeWithTopControls(webView->size(), 30.f, false);
     EXPECT_FLOAT_EQ(30.f, webView->topControls().contentOffset());
 }
 
 // Zero delta should not have any effect on top controls.
 TEST_F(TopControlsTest, MAYBE(ZeroHeightMeansNoEffect))
 {
     WebViewImpl* webView = initialize();
-    webView->setTopControlsHeight(0, false);
+    webView->resizeWithTopControls(webView->size(), 0, false);
     webView->topControls().setShownRatio(0);
     frame()->view()->getScrollableArea()->setScrollPosition(IntPoint(0, 100), ProgrammaticScroll);
 
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
 
     verticalScroll(20.f);
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 80), frame()->view()->scrollPosition());
 
     verticalScroll(-30.f);
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 110), frame()->view()->scrollPosition());
 
     webView->topControls().setShownRatio(1);
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
 }
 
 // Top controls should not hide when scrolling up past limit
 TEST_F(TopControlsTest, MAYBE(ScrollUpPastLimitDoesNotHide))
 {
     WebViewImpl* webView = initialize();
     // Initialize top controls to be shown
-    webView->setTopControlsHeight(50.f, true);
+    webView->resizeWithTopControls(webView->size(), 50.f, true);
     webView->topControls().setShownRatio(1);
     // Use 2x scale so that both visual viewport and frameview are scrollable
     webView->setPageScaleFactor(2.0);
 
     // Fully scroll frameview but visualviewport remains scrollable
     webView->mainFrame()->setScrollOffset(WebSize(0, 10000));
     visualViewport().setLocation(FloatPoint(0, 0));
     verticalScroll(-10.f);
     EXPECT_FLOAT_EQ(40, webView->topControls().contentOffset());
 
@@ skipping 11 matching lines @@
     verticalScroll(-30.f);
     // Top controls should not move because neither frameview nor visual viewport
     // are scrollable
     EXPECT_FLOAT_EQ(50.f, webView->topControls().contentOffset());
 }
 
 // Top controls should honor its constraints
 TEST_F(TopControlsTest, MAYBE(StateConstraints))
 {
     WebViewImpl* webView = initialize();
-    webView->setTopControlsHeight(50.f, false);
+    webView->resizeWithTopControls(webView->size(), 50.f, false);
     frame()->view()->getScrollableArea()->setScrollPosition(IntPoint(0, 100), ProgrammaticScroll);
 
     // Setting permitted state should not change content offset
     webView->updateTopControlsState(WebTopControlsShown, WebTopControlsShown, false);
     EXPECT_FLOAT_EQ(0.f, webView->topControls().contentOffset());
 
     // Showing is permitted
     webView->topControls().setShownRatio(1);
     EXPECT_FLOAT_EQ(50, webView->topControls().contentOffset());
 
@@ skipping 28 matching lines @@
     EXPECT_FLOAT_EQ(0, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 90), frame()->view()->scrollPosition());
 }
 
 // Ensure that top controls do not affect the layout by showing and hiding
 // except for position: fixed elements.
 TEST_F(TopControlsTest, MAYBE(DontAffectLayoutHeight))
 {
     // Initialize with the top controls showing.
     WebViewImpl* webView = initialize("percent-height.html");
-    webView->setTopControlsHeight(100.f, true);
+    webView->resizeWithTopControls(WebSize(400, 300), 100.f, true);
     webView->updateTopControlsState(
         WebTopControlsBoth, WebTopControlsShown, false);
     webView->topControls().setShownRatio(1);
-    webView->resize(WebSize(400, 300));
     webView->updateAllLifecyclePhases();
 
     ASSERT_EQ(100.f, webView->topControls().contentOffset());
 
     // When the top controls are showing, there's 300px for the layout height so
     // 50% should result in both the position:fixed and position: absolute divs
     // having 150px of height.
     Element* absPos =
         getElementById(WebString::fromUTF8("abs"));
     Element* fixedPos =
         getElementById(WebString::fromUTF8("fixed"));
     EXPECT_FLOAT_EQ(150.f, absPos->getBoundingClientRect()->height());
     EXPECT_FLOAT_EQ(150.f, fixedPos->getBoundingClientRect()->height());
 
     // The layout size on the FrameView should not include the top controls.
     EXPECT_EQ(300, frame()->view()->layoutSize(IncludeScrollbars).height());
 
     // Hide the top controls.
     verticalScroll(-100.f);
-    webView->setTopControlsHeight(100.f, false);
-    webView->resize(WebSize(400, 400));
+    webView->resizeWithTopControls(WebSize(400, 400), 100.f, false);
     webView->updateAllLifecyclePhases();
 
     ASSERT_EQ(0.f, webView->topControls().contentOffset());
 
     // Hiding the top controls shouldn't change the height of the initial
     // containing block for non-position: fixed. Position: fixed however should
     // use the entire height of the viewport however.
     EXPECT_FLOAT_EQ(150.f, absPos->getBoundingClientRect()->height());
     EXPECT_FLOAT_EQ(200.f, fixedPos->getBoundingClientRect()->height());
 
     // The layout size should not change as a result of top controls hiding.
     EXPECT_EQ(300, frame()->view()->layoutSize(IncludeScrollbars).height());
 }
 
 // Ensure that top controls do not affect vh units.
 TEST_F(TopControlsTest, MAYBE(DontAffectVHUnits))
 {
     // Initialize with the top controls showing.
     WebViewImpl* webView = initialize("vh-height.html");
-    webView->setTopControlsHeight(100.f, true);
+    webView->resizeWithTopControls(WebSize(400, 300), 100.f, true);
     webView->updateTopControlsState(
         WebTopControlsBoth, WebTopControlsShown, false);
     webView->topControls().setShownRatio(1);
-    webView->resize(WebSize(400, 300));
     webView->updateAllLifecyclePhases();
 
     ASSERT_EQ(100.f, webView->topControls().contentOffset());
 
     // 'vh' units should be based on the viewport when the top controls are
     // hidden.
     Element* absPos =
         getElementById(WebString::fromUTF8("abs"));
     Element* fixedPos =
         getElementById(WebString::fromUTF8("fixed"));
     EXPECT_FLOAT_EQ(200.f, absPos->getBoundingClientRect()->height());
     EXPECT_FLOAT_EQ(200.f, fixedPos->getBoundingClientRect()->height());
 
     // The size used for viewport units should not be reduced by the top
     // controls.
     EXPECT_EQ(400, frame()->view()->viewportSizeForViewportUnits().height());
 
     // Hide the top controls.
     verticalScroll(-100.f);
-    webView->setTopControlsHeight(100.f, false);
-    webView->resize(WebSize(400, 400));
+    webView->resizeWithTopControls(WebSize(400, 400), 100.f, false);
     webView->updateAllLifecyclePhases();
 
     ASSERT_EQ(0.f, webView->topControls().contentOffset());
 
     // vh units should be static with respect to the top controls so neighter
     // <div> should change size are a result of the top controls hiding.
     EXPECT_FLOAT_EQ(200.f, absPos->getBoundingClientRect()->height());
     EXPECT_FLOAT_EQ(200.f, fixedPos->getBoundingClientRect()->height());
 
     // The viewport size used for vh units should not change as a result of top
     // controls hiding.
     EXPECT_EQ(400, frame()->view()->viewportSizeForViewportUnits().height());
 }
 
 // Ensure that on a legacy page (there's a non-1 minimum scale) 100vh units fill
 // the viewport, with top controls hidden, when the viewport encompasses the
 // layout width.
 TEST_F(TopControlsTest, MAYBE(DontAffectVHUnitsWithScale))
 {
     // Initialize with the top controls showing.
     WebViewImpl* webView = initialize("vh-height-width-800.html");
-    webView->setTopControlsHeight(100.f, true);
+    webView->resizeWithTopControls(WebSize(400, 300), 100.f, true);
     webView->updateTopControlsState(
         WebTopControlsBoth, WebTopControlsShown, false);
     webView->topControls().setShownRatio(1);
-    webView->resize(WebSize(400, 300));
     webView->updateAllLifecyclePhases();
 
     ASSERT_EQ(100.f, webView->topControls().contentOffset());
 
     // Device viewport is 400px but the page is width=800 so minimum-scale
     // should be 0.5. This is also the scale at which the viewport fills the
     // layout width.
     ASSERT_EQ(0.5f, webView->minimumPageScaleFactor());
 
     // We should size vh units so that 100vh fills the viewport at min-scale so
     // we have to account for the minimum page scale factor. Since both boxes
     // are 50vh, and layout scale = 0.5, we have a vh viewport of 400 / 0.5 = 800
     // so we expect 50vh to be 400px.
     Element* absPos =
         getElementById(WebString::fromUTF8("abs"));
     Element* fixedPos =
         getElementById(WebString::fromUTF8("fixed"));
     EXPECT_FLOAT_EQ(400.f, absPos->getBoundingClientRect()->height());
     EXPECT_FLOAT_EQ(400.f, fixedPos->getBoundingClientRect()->height());
 
     // The size used for viewport units should not be reduced by the top
     // controls.
     EXPECT_EQ(800, frame()->view()->viewportSizeForViewportUnits().height());
 
     // Hide the top controls.
     verticalScroll(-100.f);
-    webView->setTopControlsHeight(100.f, false);
-    webView->resize(WebSize(400, 400));
+    webView->resizeWithTopControls(WebSize(400, 400), 100.f, false);
     webView->updateAllLifecyclePhases();
 
     ASSERT_EQ(0.f, webView->topControls().contentOffset());
 
     // vh units should be static with respect to the top controls so neighter
     // <div> should change size are a result of the top controls hiding.
     EXPECT_FLOAT_EQ(400.f, absPos->getBoundingClientRect()->height());
     EXPECT_FLOAT_EQ(400.f, fixedPos->getBoundingClientRect()->height());
 
     // The viewport size used for vh units should not change as a result of top
     // controls hiding.
     EXPECT_EQ(800, frame()->view()->viewportSizeForViewportUnits().height());
 }
 
 // Ensure that on a legacy page (there's a non-1 minimum scale) whose viewport
 // at minimum-scale is larger than the layout size, 100vh units fill the
 // viewport, with top controls hidden, when the viewport is scaled such that
 // its width equals the layout width.
 TEST_F(TopControlsTest, MAYBE(DontAffectVHUnitsUseLayoutSize))
 {
     // Initialize with the top controls showing.
     WebViewImpl* webView = initialize("vh-height-width-800-extra-wide.html");
-    webView->setTopControlsHeight(100.f, true);
+    webView->resizeWithTopControls(WebSize(400, 300), 100.f, true);
     webView->updateTopControlsState(
         WebTopControlsBoth, WebTopControlsShown, false);
     webView->topControls().setShownRatio(1);
-    webView->resize(WebSize(400, 300));
     webView->updateAllLifecyclePhases();
 
     ASSERT_EQ(100.f, webView->topControls().contentOffset());
 
     // Device viewport is 400px and page is width=800 but there's an element
     // that's 1600px wide so the minimum scale is 0.25 to encompass that.
     ASSERT_EQ(0.25f, webView->minimumPageScaleFactor());
 
     // The viewport will match the layout width at scale=0.5 so the height used
     // for vh should be (300 / 0.5) for the layout height + (100 / 0.5) for top
     // controls = 800.
     EXPECT_EQ(800, frame()->view()->viewportSizeForViewportUnits().height());
 }
 
+// This tests that the viewport remains anchored when top controls are brought
+// in while the document is fully scrolled. This normally causes clamping of the
+// visual viewport to keep it bounded by the layout viewport so we're testing
+// that the viewport anchoring logic is working to keep the view unchanged.
+TEST_F(TopControlsTest, MAYBE(AnchorViewportDuringTopControlsAdjustment))
+{
+    int contentHeight = 1016;
+    int layoutViewportHeight = 500;
+    int visualViewportHeight = 500;
+    int topControlsHeight = 100;
+    int pageScale = 2;
+    int minScale = 1;
+
+    // Initialize with the top controls showing.
+    WebViewImpl* webView = initialize("large-div.html");
+    webViewImpl()->setDefaultPageScaleLimits(minScale, 5);
+    webView->resizeWithTopControls(
+        WebSize(800, layoutViewportHeight),
+        topControlsHeight,
+        true);
+    webView->updateTopControlsState(
+        WebTopControlsBoth, WebTopControlsShown, false);
+    webView->topControls().setShownRatio(1);
+    webView->updateAllLifecyclePhases();
+
+    FrameView* view = frame()->view();
+    ScrollableArea* rootViewport = frame()->view()->getScrollableArea();
+
+    int expectedVisualOffset =
+        ((layoutViewportHeight + topControlsHeight / minScale) * pageScale
+        - (visualViewportHeight + topControlsHeight))
+        / pageScale;
+    int expectedLayoutOffset =
+        contentHeight - (layoutViewportHeight + topControlsHeight / minScale);
+    int expectedRootOffset = expectedVisualOffset + expectedLayoutOffset;
+
+    // Zoom in to 2X and fully scroll both viewports.
+    webView->setPageScaleFactor(pageScale);
+    {
+        webView->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollBegin));
+        webView->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollUpdate, 0, -10000));
+
+        ASSERT_EQ(0.f, webView->topControls().contentOffset());
+
+        EXPECT_EQ(expectedVisualOffset, visualViewport().location().y());
+        EXPECT_EQ(expectedLayoutOffset,
+            view->layoutViewportScrollableArea()->scrollPosition().y());
+        EXPECT_EQ(expectedRootOffset, rootViewport->scrollPosition().y());
+
+        webView->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollEnd));
+    }
+
+    // Commit the top controls resize so that the top controls do not shrink the
+    // layout size. This should not have moved any of the viewports.
+    webView->resizeWithTopControls(
+        WebSize(800, layoutViewportHeight + topControlsHeight),
+        topControlsHeight,
+        false);
+    webView->updateAllLifecyclePhases();
+    ASSERT_EQ(expectedVisualOffset, visualViewport().location().y());
+    ASSERT_EQ(expectedLayoutOffset,
+        view->layoutViewportScrollableArea()->scrollPosition().y());
+    ASSERT_EQ(expectedRootOffset, rootViewport->scrollPosition().y());
+
+    // Now scroll back up just enough to show the top controls. The top controls
+    // should shrink both viewports but the layout viewport by a greater amount.
+    // This means the visual viewport's offset must be clamped to keep it within
+    // the layout viewport. Make sure we adjust the scroll position to account
+    // for this and keep the visual viewport at the same location relative to
+    // the document (i.e. the user shouldn't see a movement).
+    {
+        webView->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollBegin));
+        webView->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollUpdate, 0, 80));
+
+        visualViewport().clampToBoundaries();
+        view->setScrollPosition(view->scrollPosition(), ProgrammaticScroll);
+
+        ASSERT_EQ(80.f, webView->topControls().contentOffset());
+        EXPECT_EQ(expectedRootOffset, rootViewport->scrollPosition().y());
+
+        webView->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollEnd));
+    }
+}
+
 } // namespace blink