Always enable passthrough raster decoder on Windows

This is a followup to:
https://chromium-review.googlesource.com/c/1444234

That previous patch worked, but only if --enable-oop-rasterization
was passed on the command line.  For finch and field trials,
it's decided much later in gpu_util.cc that oop raster should be
turned on and so the passthrough raster decoder needs to be
enabled earlier.

Bug: 627621
Change-Id: Ibe32cf715bca65faabc76954c46765ba3c18418d
Reviewed-on: https://chromium-review.googlesource.com/c/1487143
Commit-Queue: enne <enne@chromium.org>
Reviewed-by: Jonathan Backer <backer@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636588}

content/public/browser/gpu_utils.cc

@@ -116,8 +116,7 @@ const gpu::GpuPreferences GetGpuPreferencesFromCommandLine() {
   gpu_preferences.enable_passthrough_raster_decoder =
       command_line->HasSwitch(switches::kEnablePassthroughRasterDecoder);
 #if defined(OS_WIN)
-  if (gpu_preferences.enable_oop_rasterization)
-    gpu_preferences.enable_passthrough_raster_decoder = true;
+  gpu_preferences.enable_passthrough_raster_decoder = true;
 #endif
 
   gpu_preferences.enable_vulkan =

services/ws/public/cpp/gpu/context_provider_command_buffer.cc

@@ -20,6 +20,7 @@
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/memory_dump_manager.h"
+#include "build/build_config.h"
 #include "components/viz/common/gpu/context_cache_controller.h"
 #include "gpu/command_buffer/client/gles2_cmd_helper.h"
 #include "gpu/command_buffer/client/gles2_trace_implementation.h"
@@ -145,10 +146,18 @@ gpu::ContextResult ContextProviderCommandBuffer::BindToCurrentThread() {
     return bind_result_;
   }
 
-  bool allow_raster_decoder =
-      !command_buffer_->channel()->gpu_info().passthrough_cmd_decoder ||
+  // TODO(enne): remove the kEnablePassthroughRasterDecoder flag and
+  // assume it is always available.
+  bool enable_passthrough_raster_decoder =
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnablePassthroughRasterDecoder);
+#if defined(OS_WIN)
+  enable_passthrough_raster_decoder = true;
+#endif
+
+  bool allow_raster_decoder =
+      !command_buffer_->channel()->gpu_info().passthrough_cmd_decoder ||
+      enable_passthrough_raster_decoder;
   if (attributes_.context_type == gpu::CONTEXT_TYPE_WEBGPU) {
     DCHECK(!attributes_.enable_raster_interface);
     DCHECK(!attributes_.enable_gles2_interface);