Implementing document.setRootScroller API for main thread scrolling.

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

Index: third_party/WebKit/Source/web/tests/RootScrollerTest.cpp
diff --git a/third_party/WebKit/Source/web/tests/RootScrollerTest.cpp b/third_party/WebKit/Source/web/tests/RootScrollerTest.cpp
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index 0000000000000000000000000000000000000000..8fbde181d305dc8360f3bc9a9c8c9cccb01c4778
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+++ b/third_party/WebKit/Source/web/tests/RootScrollerTest.cpp
@@ -0,0 +1,473 @@
+// Copyright 2016 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 "core/page/scrolling/RootScroller.h"
+
+#include "core/frame/FrameHost.h"
+#include "core/frame/FrameView.h"
+#include "core/frame/TopControls.h"
+#include "core/html/HTMLFrameOwnerElement.h"
+#include "core/page/Page.h"
+#include "platform/testing/URLTestHelpers.h"
+#include "platform/testing/UnitTestHelpers.h"
+#include "public/platform/Platform.h"
+#include "public/platform/WebURLLoaderMockFactory.h"
+#include "public/web/WebCache.h"
+#include "public/web/WebConsoleMessage.h"
+#include "public/web/WebScriptSource.h"
+#include "public/web/WebSettings.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "web/WebLocalFrameImpl.h"
+#include "web/tests/FrameTestHelpers.h"
+#include "wtf/Vector.h"
+
+using blink::testing::runPendingTasks;
+using testing::Mock;
+
+namespace blink {
+
+namespace {
+
+class RootScrollerTestWebViewClient : public FrameTestHelpers::TestWebViewClient {
+public:
+    MOCK_METHOD4(didOverscroll, void(const WebFloatSize&, const WebFloatSize&, const WebFloatPoint&, const WebFloatSize&));
+};
+
+class RootScrollerTest : public ::testing::Test {
+public:
+    RootScrollerTest()
+        : m_baseURL("http://www.test.com/")
+    {
+        registerMockedHttpURLLoad("overflow-scrolling.html");
+        registerMockedHttpURLLoad("root-scroller.html");
+        registerMockedHttpURLLoad("root-scroller-iframe.html");
+        registerMockedHttpURLLoad("root-scroller-child.html");
+    }
+
+    ~RootScrollerTest() override
+    {
+        Platform::current()->getURLLoaderMockFactory()->unregisterAllURLs();
+        WebCache::clear();
+    }
+
+    WebViewImpl* initialize(const std::string& pageName)
+    {
+        RuntimeEnabledFeatures::setSetRootScrollerEnabled(true);
+
+        // Load a page with large body and set viewport size to 400x400 to
+        // ensure main frame is scrollable.
+        m_helper.initializeAndLoad(
+            m_baseURL + pageName, true, 0, &m_client, &configureSettings);
+
+        webViewImpl()->resize(IntSize(400, 400));
+
+        // Initialize top controls to be shown.
+        webViewImpl()->setTopControlsHeight(50.f, true);
+        webViewImpl()->topControls().setShownRatio(1);
+
+        mainFrameView()->updateAllLifecyclePhases();
+
+        return webViewImpl();
+    }
+
+    static void configureSettings(WebSettings* settings)
+    {
+        settings->setJavaScriptEnabled(true);
+        settings->setAcceleratedCompositingEnabled(true);
+        settings->setPreferCompositingToLCDTextEnabled(true);
+        // Android settings.
+        settings->setViewportEnabled(true);
+        settings->setViewportMetaEnabled(true);
+        settings->setShrinksViewportContentToFit(true);
+        settings->setMainFrameResizesAreOrientationChanges(true);
+    }
+
+    void registerMockedHttpURLLoad(const std::string& fileName)
+    {
+        URLTestHelpers::registerMockedURLFromBaseURL(
+            WebString::fromUTF8(m_baseURL.c_str()),
+            WebString::fromUTF8(fileName.c_str()));
+    }
+
+    void executeScript(const WebString& code)
+    {
+        mainWebFrame()->executeScript(WebScriptSource(code));
+        mainWebFrame()->view()->updateAllLifecyclePhases();
+        runPendingTasks();
+    }
+
+    WebGestureEvent generateEvent(
+        WebInputEvent::Type type, int deltaX = 0, int deltaY = 0)
+    {
+        WebGestureEvent event;
+        event.type = type;
+        event.sourceDevice = WebGestureDeviceTouchscreen;
+        event.x = 100;
+        event.y = 100;
+        if (type == WebInputEvent::GestureScrollUpdate) {
+            event.data.scrollUpdate.deltaX = deltaX;
+            event.data.scrollUpdate.deltaY = deltaY;
+        }
+        return event;
+    }
+
+    void verticalScroll(float deltaY)
+    {
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollBegin));
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollUpdate, 0, -deltaY));
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollEnd));
+    }
+
+    WebViewImpl* webViewImpl() const
+    {
+        return m_helper.webViewImpl();
+    }
+
+    FrameHost& frameHost() const
+    {
+        return m_helper.webViewImpl()->page()->frameHost();
+    }
+
+    LocalFrame* mainFrame() const
+    {
+        return toWebLocalFrameImpl(webViewImpl()->mainFrame())->frame();
+    }
+
+    WebLocalFrame* mainWebFrame() const
+    {
+        return toWebLocalFrameImpl(webViewImpl()->mainFrame());
+    }
+
+    FrameView* mainFrameView() const
+    {
+        return webViewImpl()->mainFrameImpl()->frame()->view();
+    }
+
+    VisualViewport& visualViewport() const
+    {
+        return frameHost().visualViewport();
+    }
+
+    RootScroller& rootScroller() const
+    {
+        return *frameHost().rootScroller();
+    }
+
+    TopControls& topControls() const
+    {
+        return frameHost().topControls();
+    }
+
+protected:
+    std::string m_baseURL;
+    RootScrollerTestWebViewClient m_client;
+    FrameTestHelpers::WebViewHelper m_helper;
+};
+
+// Test that a root scroller is set if setRootScroller isn't called on any
+// elements.
+TEST_F(RootScrollerTest, TestDefaultRootScroller)
+{
+    initialize("overflow-scrolling.html");
+
+    EXPECT_EQ(
+        mainFrame()->document()->documentElement(),
+        rootScroller().get());
+}
+
+// Tests that setting an element as the root scroller causes it to control url
+// bar hiding and overscroll.
+TEST_F(RootScrollerTest, TestSetRootScroller)
+{
+    initialize("root-scroller.html");
+
+    Element* container = mainFrame()->document()->getElementById("container");
+    TrackExceptionState exceptionState;
+    mainFrame()->document()->setRootScroller(container, exceptionState);
+    ASSERT_EQ(container, mainFrame()->document()->rootScroller());
+
+    // Content is 1000x1000, WebView size is 400x400 so max scroll is 600px.
+    double maximumScroll = 600;
+
+    webViewImpl()->handleInputEvent(
+        generateEvent(WebInputEvent::GestureScrollBegin));
+
+    {
+        // Scrolling over the #container DIV should cause the top controls to
+        // hide.
+        ASSERT_FLOAT_EQ(1, topControls().shownRatio());
+        webViewImpl()->handleInputEvent(generateEvent(
+            WebInputEvent::GestureScrollUpdate, 0, -topControls().height()));
+        ASSERT_FLOAT_EQ(0, topControls().shownRatio());
+    }
+
+    {
+        // Make sure we're actually scrolling the DIV and not the FrameView.
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollUpdate, 0, -100));
+        ASSERT_FLOAT_EQ(100, container->scrollTop());
+        ASSERT_FLOAT_EQ(0, mainFrameView()->scrollPositionDouble().y());
+    }
+
+    {
+        // Scroll 50 pixels past the end. Ensure we report overscroll rather
+        // than scrolling the FrameView.
+        EXPECT_CALL(m_client,
+            didOverscroll(
+                WebFloatSize(0, 50),
+                WebFloatSize(0, 50),
+                WebFloatPoint(100, 100),
+                WebFloatSize()));
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollUpdate, 0, -550));
+        ASSERT_FLOAT_EQ(maximumScroll, container->scrollTop());
+        ASSERT_FLOAT_EQ(0, mainFrameView()->scrollPositionDouble().y());

[tdresser, 2016/04/27 15:37:08]

Because of scroll latching, we wouldn't scroll the FrameView either way, right?
I think we need an additional gesture sequence.

[bokan, 2016/04/27 17:53:56]

Yah, this comment is misleading so I changed it. We do try a new gesture
sequence below for just this reason.

+        Mock::VerifyAndClearExpectations(&m_client);
+    }
+
+    {
+        // Continue the gesture overscroll.
+        EXPECT_CALL(m_client,
+            didOverscroll(
+                WebFloatSize(0, 20),
+                WebFloatSize(0, 70),
+                WebFloatPoint(100, 100),
+                WebFloatSize()));
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollUpdate, 0, -20));
+        ASSERT_FLOAT_EQ(maximumScroll, container->scrollTop());
+        ASSERT_FLOAT_EQ(0, mainFrameView()->scrollPositionDouble().y());
+        Mock::VerifyAndClearExpectations(&m_client);
+    }
+
+    webViewImpl()->handleInputEvent(
+        generateEvent(WebInputEvent::GestureScrollEnd));
+
+    {
+        // Make sure a new gesture scroll still won't scroll the frameview and
+        // overscrolls.
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollBegin));
+
+        EXPECT_CALL(m_client,
+            didOverscroll(
+                WebFloatSize(0, 30),
+                WebFloatSize(0, 30),
+                WebFloatPoint(100, 100),
+                WebFloatSize()));
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollUpdate, 0, -30));
+        ASSERT_FLOAT_EQ(maximumScroll, container->scrollTop());
+        ASSERT_FLOAT_EQ(0, mainFrameView()->scrollPositionDouble().y());
+        Mock::VerifyAndClearExpectations(&m_client);
+
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollEnd));
+    }
+
+    {
+        // Scrolling up should show the top controls.
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollBegin));
+
+        ASSERT_FLOAT_EQ(0, topControls().shownRatio());
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollUpdate, 0, 30));
+        ASSERT_FLOAT_EQ(0.6, topControls().shownRatio());
+
+        webViewImpl()->handleInputEvent(
+            generateEvent(WebInputEvent::GestureScrollEnd));
+    }
+}
+
+// Tests that removing the root scroller from the DOM tree resets the default
+// element to be the root scroller.
+TEST_F(RootScrollerTest, TestRemoveRootScrollerFromDom)
+{
+    initialize("root-scroller.html");
+
+    ASSERT_EQ(
+        mainFrame()->document()->documentElement(),
+        rootScroller().get());
+
+    Element* container = mainFrame()->document()->getElementById("container");
+    TrackExceptionState exceptionState;
+    mainFrame()->document()->setRootScroller(container, exceptionState);
+
+    ASSERT_EQ(container, mainFrame()->document()->rootScroller());
+
+    mainFrame()->document()->body()->removeChild(container);
+
+    ASSERT_EQ(
+        mainFrame()->document()->documentElement(),
+        mainFrame()->document()->rootScroller());
+}
+
+// Tests that setting the root scroller on an invalid element doesn't change the
+// current root scroller.
+TEST_F(RootScrollerTest, TestSetRootScrollerOnInvalidElement)
+{
+    initialize("root-scroller.html");
+
+    {
+        // Set to a non-block element. Should be rejected and a console message
+        // logged.
+        Element* element = mainFrame()->document()->getElementById("nonBlock");
+        TrackExceptionState exceptionState;
+        mainFrame()->document()->setRootScroller(element, exceptionState);
+        ASSERT_EQ(
+            mainFrame()->document()->documentElement(),
+            mainFrame()->document()->rootScroller());
+        EXPECT_TRUE(exceptionState.hadException());
+    }
+
+    {
+        // Set to an element with no size.
+        Element* element = mainFrame()->document()->getElementById("empty");
+        TrackExceptionState exceptionState;
+        mainFrame()->document()->setRootScroller(element, exceptionState);
+        ASSERT_EQ(
+            mainFrame()->document()->documentElement(),
+            mainFrame()->document()->rootScroller());
+        EXPECT_TRUE(exceptionState.hadException());
+    }
+}
+
+// Test root scroller resets to the default element when the current root
+// scroller becomes invalid.
+TEST_F(RootScrollerTest, TestRootScrollerBecomesInvalid)
+{
+    initialize("root-scroller.html");
+
+    ASSERT_EQ(
+        mainFrame()->document()->documentElement(),
+        rootScroller().get());
+
+    Element* container = mainFrame()->document()->getElementById("container");
+    TrackExceptionState exceptionState;
+    mainFrame()->document()->setRootScroller(container, exceptionState);
+
+    ASSERT_EQ(container, mainFrame()->document()->rootScroller());
+
+    executeScript(
+        "document.querySelector('#container').style.display = 'inline'");
+
+    ASSERT_EQ(
+        mainFrame()->document()->documentElement(),
+        mainFrame()->document()->rootScroller());
+}
+
+// Tests that setting the root scroller on an element within a iframe fails.

[tdresser, 2016/04/27 15:37:08]

Do you set the root scroller on an element, or do you set the root scroller to
the element?

It's a bit weird because "the root scroller" refers to an element, but being the
root scroller is a property of the element, and we sort of use them
interchangeably.

When you talk about "setting the root scroller" I think of the element which is
the root scroller, not the property which is whether or not an element is a root
scroller.

[bokan, 2016/04/27 17:53:56]

Good point. The way to think about it is that the "Root Scroller" is a property
of the document whose type is an Element. I've updated all the comments here to
be consistent with this interpretation.

+TEST_F(RootScrollerTest, TestSetRootScrollerOnElementInIframe)
+{
+    initialize("root-scroller-iframe.html");
+
+    ASSERT_EQ(
+        mainFrame()->document()->documentElement(),
+        rootScroller().get());
+
+    {
+        // Trying to set an element from a nested document should fail.
+        HTMLFrameOwnerElement* iframe = toHTMLFrameOwnerElement(
+            mainFrame()->document()->getElementById("iframe"));
+        Element* innerContainer =
+            iframe->contentDocument()->getElementById("container");
+
+        TrackExceptionState exceptionState;
+        mainFrame()->document()->setRootScroller(
+            innerContainer,
+            exceptionState);
+        EXPECT_TRUE(exceptionState.hadException());
+
+        ASSERT_EQ(
+            mainFrame()->document()->documentElement(),
+            rootScroller().get());
+    }
+
+    {
+        // Setting the iframe itself, however, should work.
+        HTMLFrameOwnerElement* iframe = toHTMLFrameOwnerElement(
+            mainFrame()->document()->getElementById("iframe"));
+
+        TrackExceptionState exceptionState;
+        mainFrame()->document()->setRootScroller(iframe, exceptionState);
+        EXPECT_FALSE(exceptionState.hadException());
+
+        ASSERT_EQ(iframe, rootScroller().get());
+    }
+}
+
+// Tests that setting the root scroller on a document within an iframe fails
+// and getting the root scroller returns the default element.
+TEST_F(RootScrollerTest, TestRootScrollerWithinIframe)
+{
+    initialize("root-scroller-iframe.html");
+
+    ASSERT_EQ(
+        mainFrame()->document()->documentElement(),
+        rootScroller().get());
+
+    {

[tdresser, 2016/04/27 15:37:08]

It might be worth splitting up these two cases into two tests.

[bokan, 2016/04/27 17:53:56]

Done.

+        // Trying to set an element within nested document should fail.
+        // rootScroller() should always return its documentElement.
+        HTMLFrameOwnerElement* iframe = toHTMLFrameOwnerElement(
+            mainFrame()->document()->getElementById("iframe"));
+
+        ASSERT_EQ(
+            iframe->contentDocument()->documentElement(),
+            iframe->contentDocument()->rootScroller());
+
+        Element* innerContainer =
+            iframe->contentDocument()->getElementById("container");
+        TrackExceptionState exceptionState;
+        iframe->contentDocument()->setRootScroller(
+            innerContainer,
+            exceptionState);
+        EXPECT_TRUE(exceptionState.hadException());
+
+        ASSERT_EQ(
+            iframe->contentDocument()->documentElement(),
+            iframe->contentDocument()->rootScroller());
+    }
+
+    {
+        // Trying to set an element from outside the iframe should fail.

[tdresser, 2016/04/27 15:37:08]

I initially misinterpreted this comment, thinking that it meant that the action
"set an element" took place outside the iframe, not that the element being
referred to was outside of the iframe.

That's a pretty silly interpretation, but it wouldn't hurt to elaborate a bit on
this (and the comment above).

[bokan, 2016/04/27 17:53:56]

Done.

+        HTMLFrameOwnerElement* iframe = toHTMLFrameOwnerElement(
+            mainFrame()->document()->getElementById("iframe"));
+        NonThrowableExceptionState nonThrow;
+        Element* body =
+            mainFrame()->document()->querySelector("body", nonThrow);
+
+        ASSERT_EQ(
+            iframe->contentDocument()->documentElement(),
+            iframe->contentDocument()->rootScroller());
+
+        TrackExceptionState exceptionState1;

[tdresser, 2016/04/27 15:37:08]

Is there any reason to not reuse the exceptionState object?

[bokan, 2016/04/27 17:53:56]

Didn't think to just clear the exception state. Done.

+        iframe->contentDocument()->setRootScroller(
+            iframe,
+            exceptionState1);
+        EXPECT_TRUE(exceptionState1.hadException());
+
+        ASSERT_EQ(
+            iframe->contentDocument()->documentElement(),
+            iframe->contentDocument()->rootScroller());
+
+        TrackExceptionState exceptionState2;
+        iframe->contentDocument()->setRootScroller(
+            body,
+            exceptionState2);
+        EXPECT_TRUE(exceptionState2.hadException());
+
+        ASSERT_EQ(
+            iframe->contentDocument()->documentElement(),
+            iframe->contentDocument()->rootScroller());
+    }
+}
+
+} // namespace
+
+} // namespace blink