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

gpu/config/gpu_util.h

 // Copyright (c) 2012 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.
 
 #ifndef GPU_CONFIG_GPU_UTIL_H_
 #define GPU_CONFIG_GPU_UTIL_H_
 
 #include <set>
 #include <string>
 
@@ skipping 16 matching lines @@
 // With provided GPUInfo, compute the driver bug workarounds and disabled
 // extensions for the current system, and append the |command_line|.
 GPU_EXPORT void ApplyGpuDriverBugWorkarounds(
     const GPUInfo& gpu_info,
     base::CommandLine* command_line);
 
 // |str| is in the format of "feature1,feature2,...,featureN".
 GPU_EXPORT void StringToFeatureSet(
     const std::string& str, std::set<int>* feature_set);
 
+// With provided command line, fill gpu_info->secondary_gpus with parsed
+// secondary vendor and device ids.
+GPU_EXPORT void ParseSecondaryGpuDevicesFromCommandLine(
+    const base::CommandLine& command_line,
+    const std::string& secondary_vendor_ids_key,

[Zhenyao Mo, 2016/04/19 21:05:27]

You really don't need to pass in the two keys here.  You can just directly use
them in the function. We never call them with two keys as empty string.

[Julien Isorce Samsung, 2016/04/20 17:19:21]

Yup but there is the "testing" version of the key. I need to figure out how to
do it then.

+    const std::string& secondary_device_ids_key,
+    GPUInfo* gpu_info);

[Zhenyao Mo, 2016/04/19 21:05:27]

Also, can you add a unit test in gpu_util_unittest.cc for this function?

[Julien Isorce Samsung, 2016/04/20 17:19:21]

Oki

+
 }  // namespace gpu
 
 #endif  // GPU_CONFIG_GPU_UTIL_H_