Fixed rotation anchoring while using a document.rootScroller.

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
index d9b834039bbf12d79ddf73ad4da3dc0a46fd631c..cdfaa2c31f21059d82ab43bda0afbd21b547f1fc 100644
--- a/third_party/WebKit/Source/web/tests/RootScrollerTest.cpp
+++ b/third_party/WebKit/Source/web/tests/RootScrollerTest.cpp
@@ -2,10 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "core/dom/ClientRect.h"
 #include "core/frame/BrowserControls.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/RootFrameViewport.h"
+#include "core/frame/VisualViewport.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/layout/LayoutBox.h"
 #include "core/layout/api/LayoutViewItem.h"
@@ -41,6 +43,7 @@ class RootScrollerTest : public ::testing::Test {
   RootScrollerTest() : m_baseURL("http://www.test.com/") {
     registerMockedHttpURLLoad("overflow-scrolling.html");
     registerMockedHttpURLLoad("root-scroller.html");
+    registerMockedHttpURLLoad("root-scroller-rotation.html");
     registerMockedHttpURLLoad("root-scroller-iframe.html");
     registerMockedHttpURLLoad("root-scroller-child.html");
   }
@@ -987,6 +990,61 @@ TEST_F(RootScrollerTest, UseVisualViewportScrollbarsIframe) {
   EXPECT_GT(containerScroller->maximumScrollOffset().height(), 0);
 }
 
+TEST_F(RootScrollerTest, RotationAnchoring) {
+  initialize("root-scroller-rotation.html");
+
+  ScrollableArea* containerScroller;
+
+  {
+    webViewImpl()->resizeWithBrowserControls(IntSize(250, 1000), 0, true);
+    mainFrameView()->updateAllLifecyclePhases();
+
+    Element* container = mainFrame()->document()->getElementById("container");
+    NonThrowableExceptionState nonThrow;
+    mainFrame()->document()->setRootScroller(container, nonThrow);
+    mainFrameView()->updateAllLifecyclePhases();
+
+    containerScroller = static_cast<PaintInvalidationCapableScrollableArea*>(
+        toLayoutBox(container->layoutObject())->getScrollableArea());
+  }
+
+  Element* target = mainFrame()->document()->getElementById("target");
+
+  // Zoom in and scroll the viewport so that the target is fully in the
+  // viewport and the visual viewport is fully scrolled within the layout
+  // viepwort.
+  {
+    int scrollX = 250 * 4;
+    int scrollY = 1000 * 4;
+
+    webViewImpl()->setPageScaleFactor(2);
+    webViewImpl()->handleInputEvent(
+        generateTouchGestureEvent(WebInputEvent::GestureScrollBegin));
+    webViewImpl()->handleInputEvent(generateTouchGestureEvent(
+        WebInputEvent::GestureScrollUpdate, -scrollX, -scrollY));
+    webViewImpl()->handleInputEvent(
+        generateTouchGestureEvent(WebInputEvent::GestureScrollEnd));
+
+    // The visual viewport should be 1.5 screens scrolled so that the target
+    // occupies the bottom quadrant of the layout viewport.
+    ASSERT_EQ((250 * 3) / 2, containerScroller->scrollOffset().width());
+    ASSERT_EQ((1000 * 3) / 2, containerScroller->scrollOffset().height());
+
+    // The visual viewport should have scrolled the last half layout viewport.
+    ASSERT_EQ((250) / 2, visualViewport().scrollOffset().width());
+    ASSERT_EQ((1000) / 2, visualViewport().scrollOffset().height());
+  }
+
+  // Now do a rotation resize.
+  webViewImpl()->resizeWithBrowserControls(IntSize(1000, 250), 50, false);
+  mainFrameView()->updateAllLifecyclePhases();
+
+  // The visual viewport should remain fully filled by the target.
+  ClientRect* rect = target->getBoundingClientRect();
+  EXPECT_EQ(rect->left(), visualViewport().scrollOffset().width());
+  EXPECT_EQ(rect->top(), visualViewport().scrollOffset().height());
+}
+
 }  // namespace
 
 }  // namespace blink