Enable Pixel_WebGLReadPixelsTabSwitch for vulkan on Android Pixel 2

Bug: 1049864
Change-Id: I9c77a8bba5251ed167aef22d2ce7ab7227ffd361
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2064179Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Peng Huang <penghuang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747367}

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

@@ -34,9 +34,6 @@ crbug.com/653538 [ win amd-0x6613 ] Pixel_GpuRasterization_BlueBox [ RetryOnFail
 [ android android-webview-instrumentation ] Pixel_Canvas2DTabSwitch [ Skip ]
 [ android android-webview-instrumentation ] Pixel_WebGLReadPixelsTabSwitch [ Skip ]
 
-# Failing on Android Pixel 2 with SkiaRenderer Vulkan
-crbug.com/1049864 [ android android-not-webview qualcomm-adreno-(tm)-540 skia-renderer use-vulkan ] Pixel_WebGLReadPixelsTabSwitch [ Failure ]
-
 # Tests running with SwiftShader are skipped on platforms where SwiftShader
 # isn't supported.
 [ mac ] Pixel_Canvas2DRedBox_SwiftShader [ Skip ]