Put transform tree building in DisplayItemPropertyTreeBuilder.

Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'Clock.cpp',
@@ skipping 259 matching lines @@
       'exported/WebCredential.cpp',
       'exported/WebCryptoAlgorithm.cpp',
       'exported/WebCryptoKey.cpp',
       'exported/WebCryptoKeyAlgorithm.cpp',
       'exported/WebCryptoResult.cpp',
       'exported/WebCursorInfo.cpp',
       'exported/WebData.cpp',
       'exported/WebDataConsumerHandle.cpp',
       'exported/WebDeviceMotionData.cpp',
       'exported/WebDeviceOrientationData.cpp',
+      'exported/WebDisplayItemClipTree.cpp',
       'exported/WebDisplayItemTransformTree.cpp',
       'exported/WebDragData.cpp',
       'exported/WebEncryptedMediaClient.cpp',
       'exported/WebEncryptedMediaKeyInformation.cpp',
       'exported/WebEncryptedMediaRequest.cpp',
       'exported/WebFederatedCredential.cpp',
       'exported/WebFileSystemCallbacks.cpp',
       'exported/WebFilterKeyframe.cpp',
       'exported/WebHTTPBody.cpp',
       'exported/WebHTTPLoadInfo.cpp',
@@ skipping 360 matching lines @@
       'graphics/paint/ClipPathRecorder.cpp',
       'graphics/paint/ClipPathRecorder.h',
       'graphics/paint/ClipRecorder.cpp',
       'graphics/paint/ClipRecorder.h',
       'graphics/paint/DisplayItem.cpp',
       'graphics/paint/DisplayItem.h',
       'graphics/paint/DisplayItemCacheSkipper.h',
       'graphics/paint/DisplayItemClient.h',
       'graphics/paint/DisplayItemList.cpp',
       'graphics/paint/DisplayItemList.h',
+      'graphics/paint/DisplayItemClipTree.cpp',
+      'graphics/paint/DisplayItemClipTree.h',
+      'graphics/paint/DisplayItemPropertyTreeBuilder.cpp',
+      'graphics/paint/DisplayItemPropertyTreeBuilder.h',
       'graphics/paint/DisplayItemTransformTree.cpp',
       'graphics/paint/DisplayItemTransformTree.h',
-      'graphics/paint/DisplayItemTransformTreeBuilder.cpp',
-      'graphics/paint/DisplayItemTransformTreeBuilder.h',
       'graphics/paint/DrawingDisplayItem.cpp',
       'graphics/paint/DrawingDisplayItem.h',
       'graphics/paint/DrawingRecorder.cpp',
       'graphics/paint/DrawingRecorder.h',
       'graphics/paint/FilterDisplayItem.cpp',
       'graphics/paint/FilterDisplayItem.h',
       'graphics/paint/FixedPositionContainerDisplayItem.cpp',
       'graphics/paint/FixedPositionContainerDisplayItem.h',
       'graphics/paint/FixedPositionDisplayItem.cpp',
       'graphics/paint/FixedPositionDisplayItem.h',
@@ skipping 295 matching lines @@
       'geometry/GeometryTestHelpers.cpp',
       'geometry/LayoutRectOutsetsTest.cpp',
       'geometry/RegionTest.cpp',
       'graphics/ContiguousContainerTest.cpp',
       'graphics/GraphicsContextTest.cpp',
       'graphics/RecordingImageBufferSurfaceTest.cpp',
       'graphics/ThreadSafeDataTransportTest.cpp',
       'graphics/filters/FilterOperationsTest.cpp',
       'graphics/filters/ImageFilterBuilderTest.cpp',
       'graphics/gpu/DrawingBufferTest.cpp',
+      'graphics/paint/DisplayItemPropertyTreeBuilderTest.cpp',
       'graphics/paint/DisplayItemListTest.cpp',
       'graphics/paint/DisplayItemTest.cpp',
-      'graphics/paint/DisplayItemTransformTreeBuilderTest.cpp',
       'image-decoders/FastSharedBufferReaderTest.cpp',
       'image-decoders/ImageDecoderTest.cpp',
       'network/FormDataTest.cpp',
       'network/HTTPParsersTest.cpp',
       'network/ResourceRequestTest.cpp',
       'scheduler/CancellableTaskFactoryTest.cpp',
       'scroll/ScrollableAreaTest.cpp',
       'testing/ArenaTestHelpers.h',
       'testing/TreeTestHelpers.cpp',
       'testing/TreeTestHelpers.h',
@@ skipping 57 matching lines @@
       ['os_posix==1 and OS!="mac"',
         {
           'platform_test_files': [
             'text/LocaleICUTest.cpp',
           ],
         }
       ],
     ],
   },
 }