Enable NV12 overlays on Windows by default

UMA data from experiment on Dev/Canary looks good.  Keep the finch flag
until M72 is branched to serve as a kill switch.

Bug: 869677
Change-Id: I2bad591041f5b4c56d1e356069ac5b0364947d0d
Reviewed-on: https://chromium-review.googlesource.com/c/1351281Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Commit-Queue: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611552}

gpu/config/gpu_finch_features.cc

@@ -42,7 +42,7 @@ const base::Feature kAndroidSurfaceControl{"AndroidSurfaceControl",
 
 // Overrides preferred overlay format to NV12 instead of YUY2.
 const base::Feature kDirectCompositionPreferNV12Overlays{
-    "DirectCompositionPreferNV12Overlays", base::FEATURE_DISABLED_BY_DEFAULT};
+    "DirectCompositionPreferNV12Overlays", base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Controls the decode acceleration of JPEG images (as opposed to camera
 // captures) in Chrome OS using the VA-API.