Enable the passthrough command decoder by default on Windows.

This ensures that the passthrough command decoder is tested on developer
builds.

BUG=738568
BUG=602688

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I3cb473c51d8c889f958827233ca67d6cf6b7fb04
Reviewed-on: https://chromium-review.googlesource.com/1075507Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562533}

gpu/config/gpu_finch_features.cc

@@ -23,7 +23,13 @@ const base::Feature kDefaultEnableGpuRasterization{
 // Use the passthrough command decoder by default.  This can be overridden with
 // the --use-cmd-decoder=passthrough or --use-cmd-decoder=validating flags.
 const base::Feature kDefaultPassthroughCommandDecoder{
-    "DefaultPassthroughCommandDecoder", base::FEATURE_DISABLED_BY_DEFAULT};
+  "DefaultPassthroughCommandDecoder",
+#if defined(OS_WIN)
+      base::FEATURE_ENABLED_BY_DEFAULT
+#else
+      base::FEATURE_DISABLED_BY_DEFAULT
+#endif
+};
 
 // Use DirectComposition layers (overlays) for video if supported. Overridden by
 // --enable-direct-composition-layers and --disable-direct-composition-layers.