Adapt and reland old position sticky implementation

cc/input/main_thread_scrolling_reason.h

 // 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.
 
 #ifndef CC_INPUT_MAIN_THREAD_SCROLLING_REASON_H_
 #define CC_INPUT_MAIN_THREAD_SCROLLING_REASON_H_
 
 namespace cc {
 
 // Ensure this stays in sync with MainThreadScrollingReason in histograms.xml.
@@ skipping 10 matching lines @@
   // Transient scrolling reasons. These are computed for each scroll begin.
   enum : uint32_t { kNonFastScrollableRegion = 1 << 5 };
   enum : uint32_t { kEventHandlers = 1 << 6 };
   enum : uint32_t { kFailedHitTest = 1 << 7 };
   enum : uint32_t { kNoScrollingLayer = 1 << 8 };
   enum : uint32_t { kNotScrollable = 1 << 9 };
   enum : uint32_t { kContinuingMainThreadScroll = 1 << 10 };
   enum : uint32_t { kNonInvertibleTransform = 1 << 11 };
   enum : uint32_t { kPageBasedScrolling = 1 << 12 };
 
+  enum : uint32_t { kHasStickyPositionObjects = 1 << 13 };
+
   // The number of flags in this struct (excluding itself).
-  enum : uint32_t { kMainThreadScrollingReasonCount = 14 };
+  enum : uint32_t { kMainThreadScrollingReasonCount = 15 };
 };
 
 }  // namespace cc
 
 #endif  // CC_INPUT_MAIN_THREAD_SCROLLING_REASON_H_