InPrePaint document state and PrePaintTreeWalk class

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 2094 matching lines @@
             'paint/PaintPhase.cpp',
             'paint/PaintPhase.h',
             'paint/PaintPropertyTreeBuilder.cpp',
             'paint/PaintPropertyTreeBuilder.h',
             'paint/PaintPropertyTreePrinter.cpp',
             'paint/PaintPropertyTreePrinter.h',
             'paint/PaintTiming.cpp',
             'paint/PaintTiming.h',
             'paint/PartPainter.cpp',
             'paint/PartPainter.h',
+            'paint/PrePaintTreeWalk.cpp',
+            'paint/PrePaintTreeWalk.h',
             'paint/ReplacedPainter.cpp',
             'paint/ReplacedPainter.h',
             'paint/ReplicaPainter.cpp',
             'paint/ReplicaPainter.h',
             'paint/RootInlineBoxPainter.cpp',
             'paint/RootInlineBoxPainter.h',
             'paint/RoundedInnerRectClipper.cpp',
             'paint/RoundedInnerRectClipper.h',
             'paint/SVGClipPainter.cpp',
             'paint/SVGClipPainter.h',
@@ skipping 2018 matching lines @@
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'timing/PerformanceBaseTest.cpp',
             'timing/PerformanceObserverTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'workers/WorkerThreadTestHelper.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }