Compute snap offsets (both repeat and element based)

third_party/WebKit/Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 1993 matching lines @@
             'page/TouchAdjustment.h',
             'page/TouchDisambiguation.cpp',
             'page/TouchDisambiguation.h',
             'page/WindowFeatures.cpp',
             'page/scrolling/OverscrollController.cpp',
             'page/scrolling/OverscrollController.h',
             'page/scrolling/RootScroller.cpp',
             'page/scrolling/RootScroller.h',
             'page/scrolling/ScrollingCoordinator.cpp',
             'page/scrolling/ScrollingCoordinator.h',
+            'page/scrolling/SnapCoordinator.cpp',
+            'page/scrolling/SnapCoordinator.h',
             'page/scrolling/ScrollCustomizationCallbacks.cpp',
             'page/scrolling/ScrollCustomizationCallbacks.h',
             'page/scrolling/ScrollState.cpp',
             'page/scrolling/ScrollState.h',
             'page/scrolling/ScrollStateCallback.cpp',
             'page/scrolling/ScrollStateCallback.h',
             'page/scrolling/StickyPositionScrollingConstraints.cpp',
             'page/scrolling/StickyPositionScrollingConstraints.h',
             'page/scrolling/ViewportScrollCallback.cpp',
             'page/scrolling/ViewportScrollCallback.h',
@@ skipping 2066 matching lines @@
             'origin_trials/OriginTrialContextTest.cpp',
             'page/ChromeClientTest.cpp',
             'page/ContextMenuControllerTest.cpp',
             'page/EventSourceParserTest.cpp',
             'page/FocusControllerTest.cpp',
             'page/NetworkStateNotifierTest.cpp',
             'page/PagePopupClientTest.cpp',
             'page/PrintContextTest.cpp',
             'page/WindowFeaturesTest.cpp',
             'page/scrolling/ScrollStateTest.cpp',
+            'page/scrolling/SnapCoordinatorTest.cpp',
             'paint/LayerClipRecorderTest.cpp',
             'paint/LayoutObjectDrawingRecorderTest.cpp',
             'paint/NinePieceImageGridTest.cpp',
             'paint/PaintControllerPaintTest.cpp',
             'paint/PaintControllerPaintTest.h',
             'paint/PaintInfoTest.cpp',
             'paint/PaintLayerPainterTest.cpp',
             'paint/PaintPropertyTreeBuilderTest.cpp',
             'paint/TableCellPainterTest.cpp',
             'paint/TextPainterTest.cpp',
             'streams/ReadableStreamOperationsTest.cpp',
             'streams/ReadableStreamReaderTest.cpp',
             'streams/ReadableStreamTest.cpp',
             'style/ComputedStyleTest.cpp',
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'svg/SVGPathParserTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'workers/WorkerThreadTestHelper.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }