Adapt and reland old position sticky implementation

Source/platform/graphics/CompositingReasons.h

 // 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.
 
 #ifndef CompositingReasons_h
 #define CompositingReasons_h
 
 #include "platform/PlatformExport.h"
 #include "wtf/MathExtras.h"
 #include <stdint.h>
 
 namespace blink {
 
 const uint64_t CompositingReasonNone                                     = 0;
 const uint64_t CompositingReasonAll                                      = ~static_cast<uint64_t>(0);
 
 // Intrinsic reasons that can be known right away by the layer
 const uint64_t CompositingReason3DTransform                              = UINT64_C(1) << 0;
 const uint64_t CompositingReasonVideo                                    = UINT64_C(1) << 1;
 const uint64_t CompositingReasonCanvas                                   = UINT64_C(1) << 2;
 const uint64_t CompositingReasonPlugin                                   = UINT64_C(1) << 3;
 const uint64_t CompositingReasonIFrame                                   = UINT64_C(1) << 4;
 const uint64_t CompositingReasonBackfaceVisibilityHidden                 = UINT64_C(1) << 5;
 const uint64_t CompositingReasonActiveAnimation                          = UINT64_C(1) << 6;
 const uint64_t CompositingReasonTransitionProperty                       = UINT64_C(1) << 7;
 const uint64_t CompositingReasonPositionFixed                            = UINT64_C(1) << 8;
-const uint64_t CompositingReasonOverflowScrollingTouch                   = UINT64_C(1) << 9;
-const uint64_t CompositingReasonOverflowScrollingParent                  = UINT64_C(1) << 10;
-const uint64_t CompositingReasonOutOfFlowClipping                        = UINT64_C(1) << 11;
-const uint64_t CompositingReasonVideoOverlay                             = UINT64_C(1) << 12;
-const uint64_t CompositingReasonWillChangeCompositingHint                = UINT64_C(1) << 13;
-const uint64_t CompositingReasonBackdropFilter                           = UINT64_C(1) << 14;
+const uint64_t CompositingReasonPositionSticky                           = UINT64_C(1) << 9;
+const uint64_t CompositingReasonOverflowScrollingTouch                   = UINT64_C(1) << 10;
+const uint64_t CompositingReasonOverflowScrollingParent                  = UINT64_C(1) << 11;
+const uint64_t CompositingReasonOutOfFlowClipping                        = UINT64_C(1) << 12;
+const uint64_t CompositingReasonVideoOverlay                             = UINT64_C(1) << 13;
+const uint64_t CompositingReasonWillChangeCompositingHint                = UINT64_C(1) << 14;
+const uint64_t CompositingReasonBackdropFilter                           = UINT64_C(1) << 15;
 
 // Overlap reasons that require knowing what's behind you in paint-order before knowing the answer
-const uint64_t CompositingReasonAssumedOverlap                           = UINT64_C(1) << 15;
-const uint64_t CompositingReasonOverlap                                  = UINT64_C(1) << 16;
-const uint64_t CompositingReasonNegativeZIndexChildren                   = UINT64_C(1) << 17;
-const uint64_t CompositingReasonScrollsWithRespectToSquashingLayer       = UINT64_C(1) << 18;
-const uint64_t CompositingReasonSquashingSparsityExceeded                = UINT64_C(1) << 19;
-const uint64_t CompositingReasonSquashingClippingContainerMismatch       = UINT64_C(1) << 20;
-const uint64_t CompositingReasonSquashingOpacityAncestorMismatch         = UINT64_C(1) << 21;
-const uint64_t CompositingReasonSquashingTransformAncestorMismatch       = UINT64_C(1) << 22;
-const uint64_t CompositingReasonSquashingFilterMismatch                  = UINT64_C(1) << 23;
-const uint64_t CompositingReasonSquashingWouldBreakPaintOrder            = UINT64_C(1) << 24;
-const uint64_t CompositingReasonSquashingVideoIsDisallowed               = UINT64_C(1) << 25;
-const uint64_t CompositingReasonSquashedLayerClipsCompositingDescendants = UINT64_C(1) << 26;
-const uint64_t CompositingReasonSquashingLayoutPartIsDisallowed          = UINT64_C(1) << 27;
-const uint64_t CompositingReasonSquashingReflectionIsDisallowed          = UINT64_C(1) << 28;
-const uint64_t CompositingReasonSquashingBlendingIsDisallowed            = UINT64_C(1) << 29;
-const uint64_t CompositingReasonSquashingNearestFixedPositionMismatch    = UINT64_C(1) << 30;
-const uint64_t CompositingReasonScrollChildWithCompositedDescendants     = UINT64_C(1) << 31;
+const uint64_t CompositingReasonAssumedOverlap                           = UINT64_C(1) << 16;
+const uint64_t CompositingReasonOverlap                                  = UINT64_C(1) << 17;
+const uint64_t CompositingReasonNegativeZIndexChildren                   = UINT64_C(1) << 18;
+const uint64_t CompositingReasonScrollsWithRespectToSquashingLayer       = UINT64_C(1) << 19;
+const uint64_t CompositingReasonSquashingSparsityExceeded                = UINT64_C(1) << 20;
+const uint64_t CompositingReasonSquashingClippingContainerMismatch       = UINT64_C(1) << 21;
+const uint64_t CompositingReasonSquashingOpacityAncestorMismatch         = UINT64_C(1) << 22;
+const uint64_t CompositingReasonSquashingTransformAncestorMismatch       = UINT64_C(1) << 23;
+const uint64_t CompositingReasonSquashingFilterMismatch                  = UINT64_C(1) << 24;
+const uint64_t CompositingReasonSquashingWouldBreakPaintOrder            = UINT64_C(1) << 25;
+const uint64_t CompositingReasonSquashingVideoIsDisallowed               = UINT64_C(1) << 26;
+const uint64_t CompositingReasonSquashedLayerClipsCompositingDescendants = UINT64_C(1) << 27;
+const uint64_t CompositingReasonSquashingLayoutPartIsDisallowed          = UINT64_C(1) << 28;
+const uint64_t CompositingReasonSquashingReflectionIsDisallowed          = UINT64_C(1) << 29;
+const uint64_t CompositingReasonSquashingBlendingIsDisallowed            = UINT64_C(1) << 30;
+const uint64_t CompositingReasonSquashingNearestFixedPositionMismatch    = UINT64_C(1) << 31;
+const uint64_t CompositingReasonScrollChildWithCompositedDescendants     = UINT64_C(1) << 32;
 
 // Subtree reasons that require knowing what the status of your subtree is before knowing the answer
-const uint64_t CompositingReasonTransformWithCompositedDescendants       = UINT64_C(1) << 32;
-const uint64_t CompositingReasonOpacityWithCompositedDescendants         = UINT64_C(1) << 33;
-const uint64_t CompositingReasonMaskWithCompositedDescendants            = UINT64_C(1) << 34;
-const uint64_t CompositingReasonReflectionWithCompositedDescendants      = UINT64_C(1) << 35;
-const uint64_t CompositingReasonFilterWithCompositedDescendants          = UINT64_C(1) << 36;
-const uint64_t CompositingReasonBlendingWithCompositedDescendants        = UINT64_C(1) << 37;
-const uint64_t CompositingReasonClipsCompositingDescendants              = UINT64_C(1) << 38;
-const uint64_t CompositingReasonPerspectiveWith3DDescendants             = UINT64_C(1) << 39;
-const uint64_t CompositingReasonPreserve3DWith3DDescendants              = UINT64_C(1) << 40;
-const uint64_t CompositingReasonReflectionOfCompositedParent             = UINT64_C(1) << 41;
-const uint64_t CompositingReasonIsolateCompositedDescendants             = UINT64_C(1) << 42;
+const uint64_t CompositingReasonTransformWithCompositedDescendants       = UINT64_C(1) << 33;
+const uint64_t CompositingReasonOpacityWithCompositedDescendants         = UINT64_C(1) << 34;
+const uint64_t CompositingReasonMaskWithCompositedDescendants            = UINT64_C(1) << 35;
+const uint64_t CompositingReasonReflectionWithCompositedDescendants      = UINT64_C(1) << 36;
+const uint64_t CompositingReasonFilterWithCompositedDescendants          = UINT64_C(1) << 37;
+const uint64_t CompositingReasonBlendingWithCompositedDescendants        = UINT64_C(1) << 38;
+const uint64_t CompositingReasonClipsCompositingDescendants              = UINT64_C(1) << 39;
+const uint64_t CompositingReasonPerspectiveWith3DDescendants             = UINT64_C(1) << 40;
+const uint64_t CompositingReasonPreserve3DWith3DDescendants              = UINT64_C(1) << 41;
+const uint64_t CompositingReasonReflectionOfCompositedParent             = UINT64_C(1) << 42;
+const uint64_t CompositingReasonIsolateCompositedDescendants             = UINT64_C(1) << 43;
 
 // The root layer is a special case that may be forced to be a layer, but also it needs to be
 // a layer if anything else in the subtree is composited.
-const uint64_t CompositingReasonRoot                                     = UINT64_C(1) << 43;
+const uint64_t CompositingReasonRoot                                     = UINT64_C(1) << 44;
 
 // CompositedLayerMapping internal hierarchy reasons
-const uint64_t CompositingReasonLayerForAncestorClip                     = UINT64_C(1) << 44;
-const uint64_t CompositingReasonLayerForDescendantClip                   = UINT64_C(1) << 45;
-const uint64_t CompositingReasonLayerForPerspective                      = UINT64_C(1) << 46;
-const uint64_t CompositingReasonLayerForHorizontalScrollbar              = UINT64_C(1) << 47;
-const uint64_t CompositingReasonLayerForVerticalScrollbar                = UINT64_C(1) << 48;
-const uint64_t CompositingReasonLayerForOverflowControlsHost             = UINT64_C(1) << 49;
-const uint64_t CompositingReasonLayerForScrollCorner                     = UINT64_C(1) << 50;
-const uint64_t CompositingReasonLayerForScrollingContents                = UINT64_C(1) << 51;
-const uint64_t CompositingReasonLayerForScrollingContainer               = UINT64_C(1) << 52;
-const uint64_t CompositingReasonLayerForSquashingContents                = UINT64_C(1) << 53;
-const uint64_t CompositingReasonLayerForSquashingContainer               = UINT64_C(1) << 54;
-const uint64_t CompositingReasonLayerForForeground                       = UINT64_C(1) << 55;
-const uint64_t CompositingReasonLayerForBackground                       = UINT64_C(1) << 56;
-const uint64_t CompositingReasonLayerForMask                             = UINT64_C(1) << 57;
-const uint64_t CompositingReasonLayerForClippingMask                     = UINT64_C(1) << 58;
-const uint64_t CompositingReasonLayerForScrollingBlockSelection          = UINT64_C(1) << 59;
+const uint64_t CompositingReasonLayerForAncestorClip                     = UINT64_C(1) << 45;
+const uint64_t CompositingReasonLayerForDescendantClip                   = UINT64_C(1) << 46;
+const uint64_t CompositingReasonLayerForPerspective                      = UINT64_C(1) << 47;
+const uint64_t CompositingReasonLayerForHorizontalScrollbar              = UINT64_C(1) << 48;
+const uint64_t CompositingReasonLayerForVerticalScrollbar                = UINT64_C(1) << 49;
+const uint64_t CompositingReasonLayerForOverflowControlsHost             = UINT64_C(1) << 50;
+const uint64_t CompositingReasonLayerForScrollCorner                     = UINT64_C(1) << 51;
+const uint64_t CompositingReasonLayerForScrollingContents                = UINT64_C(1) << 52;
+const uint64_t CompositingReasonLayerForScrollingContainer               = UINT64_C(1) << 53;
+const uint64_t CompositingReasonLayerForSquashingContents                = UINT64_C(1) << 54;
+const uint64_t CompositingReasonLayerForSquashingContainer               = UINT64_C(1) << 55;
+const uint64_t CompositingReasonLayerForForeground                       = UINT64_C(1) << 56;
+const uint64_t CompositingReasonLayerForBackground                       = UINT64_C(1) << 57;
+const uint64_t CompositingReasonLayerForMask                             = UINT64_C(1) << 58;
+const uint64_t CompositingReasonLayerForClippingMask                     = UINT64_C(1) << 59;
+const uint64_t CompositingReasonLayerForScrollingBlockSelection          = UINT64_C(1) << 60;
 
 // Composited elements with inline transforms trigger assumed overlap so that
 // we can update their transforms quickly.
-const uint64_t CompositingReasonInlineTransform                          = UINT64_C(1) << 60;
+const uint64_t CompositingReasonInlineTransform                          = UINT64_C(1) << 61;
 
-const uint64_t CompositingReasonCompositorProxy                          = UINT64_C(1) << 61;
+const uint64_t CompositingReasonCompositorProxy                          = UINT64_C(1) << 62;
 
 // Various combinations of compositing reasons are defined here also, for more intutive and faster bitwise logic.
 const uint64_t CompositingReasonComboAllDirectReasons =
     CompositingReason3DTransform
     | CompositingReasonVideo
     | CompositingReasonCanvas
     | CompositingReasonPlugin
     | CompositingReasonIFrame
     | CompositingReasonBackfaceVisibilityHidden
     | CompositingReasonActiveAnimation
     | CompositingReasonTransitionProperty
     | CompositingReasonPositionFixed
+    | CompositingReasonPositionSticky
     | CompositingReasonOverflowScrollingTouch
     | CompositingReasonOverflowScrollingParent
     | CompositingReasonOutOfFlowClipping
     | CompositingReasonVideoOverlay
     | CompositingReasonWillChangeCompositingHint
     | CompositingReasonCompositorProxy
     | CompositingReasonBackdropFilter;
 
 const uint64_t CompositingReasonComboAllDirectStyleDeterminedReasons =
     CompositingReason3DTransform
@@ skipping 76 matching lines @@
     const char* shortName;
     const char* description;
 };
 
 PLATFORM_EXPORT extern const CompositingReasonStringMap kCompositingReasonStringMap[];
 PLATFORM_EXPORT extern size_t kNumberOfCompositingReasons;
 
 } // namespace blink
 
 #endif // CompositingReasons_h