Hook up CSSPaintValue::image to CSS Paint API callback.

third_party/WebKit/Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'ContentDecryptionModuleResult.h',
@@ skipping 559 matching lines @@
       'graphics/ContentLayerDelegate.h',
       'graphics/ContiguousContainer.cpp',
       'graphics/ContiguousContainer.h',
       'graphics/CrossfadeGeneratedImage.cpp',
       'graphics/CrossfadeGeneratedImage.h',
       'graphics/DecodingImageGenerator.cpp',
       'graphics/DecodingImageGenerator.h',
       'graphics/DeferredImageDecoder.cpp',
       'graphics/DeferredImageDecoder.h',
       'graphics/ExpensiveCanvasHeuristicParameters.h',
+      'graphics/PaintGeneratedImage.cpp',
+      'graphics/PaintGeneratedImage.h',
       'graphics/PicturePattern.cpp',
       'graphics/PicturePattern.h',
       'graphics/PictureSnapshot.h',
       'graphics/PictureSnapshot.cpp',
       'graphics/DrawLooperBuilder.cpp',
       'graphics/DrawLooperBuilder.h',
       'graphics/FirstPaintInvalidationTracking.cpp',
       'graphics/FirstPaintInvalidationTracking.h',
       'graphics/FrameData.cpp',
       'graphics/FrameData.h',
@@ skipping 712 matching lines @@
       ['OS!="mac"',
         {
           'platform_test_files': [
             'scroll/ScrollAnimatorTest.cpp',
           ],
         }
       ],
     ],
   },
 }