Do not lose secondary gpus and make sure to have an active gpu on multiple gpu configurations

gpu/config/gpu_switches.cc

 // Copyright 2015 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/config/gpu_switches.h"
 
 namespace switches {
 
 // Pass a set of GpuDriverBugWorkaroundType ids, seperated by ','.
 const char kGpuDriverBugWorkarounds[] = "gpu-driver-bug-workarounds";
 
+// Passes secondary gpu vendor ids from browser process to GPU process.
+const char kGpuSecondaryVendorIDs[] = "gpu-secondary-vendor-ids";
+
+// Passes secondary gpu device ids from browser process to GPU process.
+const char kGpuSecondaryDeviceIDs[] = "gpu-secondary-device-ids";
+
 // Testing switch to not launch the gpu process for full gpu info collection.
 const char kGpuTestingNoCompleteInfoCollection[] =
     "gpu-no-complete-info-collection";
 
 // Override os version from GpuControlList::MakeDecision.
 const char kGpuTestingOsVersion[] = "gpu-testing-os-version";
 
 // Override gpu vendor id from the GpuInfoCollector.
 const char kGpuTestingVendorId[] = "gpu-testing-vendor-id";
 
 // Override gpu device id from the GpuInfoCollector.
 const char kGpuTestingDeviceId[] = "gpu-testing-device-id";
 
+// Override secondary gpu vendor ids from the GpuInfoCollector.
+const char kGpuTestingSecondaryVendorIDs[] = "gpu-testing-secondary-vendor-ids";
+
+// Override secondary gpu device ids from the GpuInfoCollector.
+const char kGpuTestingSecondaryDeviceIDs[] = "gpu-testing-secondary-device-ids";
+
 // Override gl vendor from the GpuInfoCollector.
 const char kGpuTestingGLVendor[] = "gpu-testing-gl-vendor";
 
 // Override gl renderer from the GpuInfoCollector.
 const char kGpuTestingGLRenderer[] = "gpu-testing-gl-renderer";
 
 // Override gl version from the GpuInfoCollector.
 const char kGpuTestingGLVersion[] = "gpu-testing-gl-version";
 
 }  // namespace switches