MainFrame scrollbars should work with RFV instead of FV

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

 // Copyright 2014 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/frame/VisualViewport.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/BrowserControls.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
@@ skipping 287 matching lines @@
       expectedLocation,
       frameView.getScrollableArea()->visibleContentRect().location());
 
   webViewImpl()->resize(IntSize(800, 600));
 
   EXPECT_POINT_EQ(
       expectedLocation,
       frameView.getScrollableArea()->visibleContentRect().location());
 }
 
+// Test the main frame scrollbars take visual viewport into account.
+TEST_P(VisualViewportTest, VerifyScrollbarBehavior) {
+  // TODO(ymalik): With root layer scrolling enabled, the scroller returned
+  // by FrameView is PaintLayerScrollableArea. PLSA doesn't know about the
+  // visual viewport and thus, scrollbars aren't added when we zoom in.
+  if (RuntimeEnabledFeatures::rootLayerScrollingEnabled())

[bokan, 2016/11/03 19:59:59]

Run the test but change the expectations below based on bool rootLayerScrolls =
GetParam().

[ymalik, 2016/11/04 18:54:18]

Good tip. Done.

+    return;
+
+  initializeWithDesktopSettings();
+
+  registerMockedHttpURLLoad("200-by-800-viewport.html");
+  navigateTo(m_baseURL + "200-by-800-viewport.html");
+
+  webViewImpl()->resize(IntSize(300, 200));
+
+  ScrollableArea* scroller = frame()->view()->getScrollableArea();
+
+  // Initially, there is no horizontal scrollbar since the content fits.
+  EXPECT_FALSE(scroller->horizontalScrollbar());
+  EXPECT_TRUE(scroller->verticalScrollbar());
+
+  // Scroll layout viewport.
+  webViewImpl()->mainFrame()->setScrollOffset(WebSize(0, 200));
+  EXPECT_SIZE_EQ(ScrollOffset(0, 200), scroller->scrollOffset());
+
+  webViewImpl()->setPageScaleFactor(2.0);
+
+  // Pinch-zooming should add horizontal scrollbar.
+  EXPECT_TRUE(scroller->horizontalScrollbar());
+  EXPECT_TRUE(scroller->verticalScrollbar());
+
+  // Scroll visual viewport.
+  VisualViewport& visualViewport =
+      frame()->page()->frameHost().visualViewport();
+  visualViewport.setLocation(FloatPoint(100, 100));
+  EXPECT_FLOAT_SIZE_EQ(FloatSize(100, 100), visualViewport.scrollOffset());
+
+  // Scrollbar offset should take visual viewport into account.
+  EXPECT_FLOAT_EQ(100, scroller->horizontalScrollbar()->currentPos());
+  EXPECT_FLOAT_EQ(300, scroller->verticalScrollbar()->currentPos());
+}
+
 // Test that the VisualViewport works as expected in case of a scaled
 // and scrolled viewport - scroll down.
 TEST_P(VisualViewportTest, TestResizeAfterVerticalScroll) {
 /*
                  200                                 200
         |                   |               |                   |
         |                   |               |                   |
         |                   | 800           |                   | 800
         |-------------------|               |                   |
         |                   |               |                   |
@@ skipping 1793 matching lines @@
   webViewImpl()->resize(IntSize(600, 800));
 
   EXPECT_SIZE_EQ(ScrollOffset(),
                  frameView.layoutViewportScrollableArea()->scrollOffset());
   EXPECT_EQ(600, scroller->scrollTop());
 
   RuntimeEnabledFeatures::setSetRootScrollerEnabled(wasRootScrollerEnabled);
 }
 
 }  // namespace