Run the WebGL conformance tests with the passthrough command decoder.

gpu/ipc/service/gpu_init.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/ipc/service/gpu_init.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
@@ skipping 140 matching lines @@
   // Get vendor_id, device_id, driver_version from browser process through
   // commandline switches.
   GetGpuInfoFromCommandLine(gpu_info_, command_line);
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
   if (gpu_info_.gpu.vendor_id == 0x10de &&  // NVIDIA
       gpu_info_.driver_vendor == "NVIDIA" && !CanAccessNvidiaDeviceFile())
     return false;
 #endif
   gpu_info_.in_process_gpu = false;
 
+  gpu_info_.passthrough_cmd_decoder =
+      command_line.HasSwitch(switches::kUsePassthroughCmdDecoder);
+
   sandbox_helper_->PreSandboxStartup();
 
 #if defined(OS_LINUX)
   // On Chrome OS ARM Mali, GPU driver userspace creates threads when
   // initializing a GL context, so start the sandbox early.
   if (command_line.HasSwitch(switches::kGpuSandboxStartEarly))
     gpu_info_.sandboxed =
         sandbox_helper_->EnsureSandboxInitialized(watchdog_thread_.get());
 #endif  // defined(OS_LINUX)
 
@@ skipping 56 matching lines @@
     watchdog_thread_ = gpu::GpuWatchdogThread::Create();
   }
 
   if (!gpu_info_.sandboxed)
     gpu_info_.sandboxed =
         sandbox_helper_->EnsureSandboxInitialized(watchdog_thread_.get());
   return true;
 }
 
 }  // namespace gpu