Use scroll-boundary-behavior to control overscroll-refresh/glow on android.

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 183 matching lines @@
 #include "core/loader/FrameLoader.h"
 #include "core/loader/NavigationScheduler.h"
 #include "core/loader/PrerendererClient.h"
 #include "core/loader/appcache/ApplicationCacheHost.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/EventWithHitTestResults.h"
 #include "core/page/FocusController.h"
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
 #include "core/page/PointerLockController.h"
+#include "core/page/scrolling/OverscrollController.h"
 #include "core/page/scrolling/RootScrollerController.h"
 #include "core/page/scrolling/ScrollStateCallback.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/page/scrolling/SnapCoordinator.h"
 #include "core/page/scrolling/TopDocumentRootScrollerController.h"
 #include "core/probe/CoreProbes.h"
 #include "core/resize_observer/ResizeObserverController.h"
 #include "core/svg/SVGDocumentExtensions.h"
 #include "core/svg/SVGScriptElement.h"
 #include "core/svg/SVGTitleElement.h"
@@ skipping 1750 matching lines @@
       overflow_y = EOverflow::kAuto;
     if (overflow_anchor == EOverflowAnchor::kVisible)
       overflow_anchor = EOverflowAnchor::kAuto;
     // Column-gap is (ab)used by the current paged overflow implementation (in
     // lack of other ways to specify gaps between pages), so we have to
     // propagate it too.
     column_gap = overflow_style->ColumnGap();
   }
 
   ScrollSnapType snap_type = overflow_style->GetScrollSnapType();
+  EScrollBoundaryBehavior scroll_boundary_behavior_x =
+      overflow_style->ScrollBoundaryBehaviorX();
+  EScrollBoundaryBehavior scroll_boundary_behavior_y =
+      overflow_style->ScrollBoundaryBehaviorY();
+  using ScrollBoundaryBehaviorType =
+      WebScrollBoundaryBehavior::ScrollBoundaryBehaviorType;
+  if (RuntimeEnabledFeatures::CSSScrollBoundaryBehaviorEnabled()) {
+    GetPage()->GetOverscrollController().SetScrollBoundaryBehavior(

[majidvp, 2017/07/21 15:24:12]

If I understand this correctly, the current logic allows any document in
the page to control the overscroll navigation behavior of the page. Meaning that
if I have this css property on an iframe then it will prevent the navigation.
This is incorrect.

We should only allow the top level document to control this behavior. Which I
think means limiting this to when |Document::IsInMainFrame()| is true.

Also, this suggests to me that we are missing a few tests. For example there is
no test covering this. I suspect you can add tests to WebFrameTest to ensure we
receive the correct values according to the css property and whether this is the
main frame or not.

[sunyunjia, 2017/07/25 20:20:55]

Done.

+        WebScrollBoundaryBehavior(
+            static_cast<ScrollBoundaryBehaviorType>(scroll_boundary_behavior_x),
+            static_cast<ScrollBoundaryBehaviorType>(
+                scroll_boundary_behavior_y)));
+  }
 
   RefPtr<ComputedStyle> viewport_style = GetLayoutViewItem().MutableStyle();
   if (viewport_style->GetWritingMode() != root_writing_mode ||
       viewport_style->Direction() != root_direction ||
       viewport_style->VisitedDependentColor(CSSPropertyBackgroundColor) !=
           background_color ||
       viewport_style->BackgroundLayers() != background_layers ||
       viewport_style->ImageRendering() != image_rendering ||
       viewport_style->OverflowAnchor() != overflow_anchor ||
       viewport_style->OverflowX() != overflow_x ||
       viewport_style->OverflowY() != overflow_y ||
       viewport_style->ColumnGap() != column_gap ||
-      viewport_style->GetScrollSnapType() != snap_type) {
+      viewport_style->GetScrollSnapType() != snap_type ||
+      viewport_style->ScrollBoundaryBehaviorX() != scroll_boundary_behavior_x ||
+      viewport_style->ScrollBoundaryBehaviorY() != scroll_boundary_behavior_y) {
     RefPtr<ComputedStyle> new_style = ComputedStyle::Clone(*viewport_style);
     new_style->SetWritingMode(root_writing_mode);
     new_style->SetDirection(root_direction);
     new_style->SetBackgroundColor(background_color);
     new_style->AccessBackgroundLayers() = background_layers;
     new_style->SetImageRendering(image_rendering);
     new_style->SetOverflowAnchor(overflow_anchor);
     new_style->SetOverflowX(overflow_x);
     new_style->SetOverflowY(overflow_y);
     new_style->SetColumnGap(column_gap);
     new_style->SetScrollSnapType(snap_type);
+    new_style->SetScrollBoundaryBehaviorX(scroll_boundary_behavior_x);
+    new_style->SetScrollBoundaryBehaviorY(scroll_boundary_behavior_y);
     GetLayoutViewItem().SetStyle(new_style);
     SetupFontBuilder(*new_style);
   }
 
   if (body) {
     if (const ComputedStyle* style = body->GetComputedStyle()) {
       if (style->Direction() != root_direction ||
           style->GetWritingMode() != root_writing_mode)
         body->SetNeedsStyleRecalc(kSubtreeStyleChange,
                                   StyleChangeReasonForTracing::Create(
@@ skipping 4960 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (blink::Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->Url().GetString().Utf8().data());
 }
 #endif