Re-enable Pixel_CSS3DBlueBox for SkiaRenderer

The image diff was approved. Re-enable the test

TBR=ynovikov@chromium.org
TEST=Pixel_CSS3DBlueBox

Bug: 976370
Change-Id: I99d457c83e72982525f6ef4b9d2ce16d1b1101e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1724890Reviewed-by: Jonathan Ross <jonross@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jonathan Ross <jonross@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682096}

content/test/gpu/gpu_tests/test_expectations/pixel_expectations.txt

@@ -173,9 +173,6 @@ crbug.com/974380 [ win ] Pixel_OffscreenCanvasUnaccelerated2DGPUCompositingWorke
 crbug.com/974380 [ mac ] Pixel_OffscreenCanvasUnaccelerated2DGPUCompositingWorker [ Skip ]
 crbug.com/974383 [ mac ] Pixel_CanvasDisplayLinearRGBAccelerated2D [ Skip ]
 
-# Fails when the browser feature SkiaRenderer is enabled
-crbug.com/976370 [ skia-renderer ] Pixel_CSS3DBlueBox [ Skip ]
-
 # Fails when the browser features SkiaRenderer & Vulkan are enabled on Linux
 crbug.com/984973 [ linux skia-renderer use-vulkan ] Pixel_CanvasDisplayLinearRGBUnaccelerated2D [ Skip ]
 crbug.com/984973 [ linux skia-renderer use-vulkan ] Pixel_CanvasDisplayLinearRGBUnaccelerated2DGPUCompositing [ Skip ]