Change GPUInfo to handle multiple GPUs.

content/browser/gpu/gpu_data_manager_impl.h

Index: content/browser/gpu/gpu_data_manager_impl.h
===================================================================
--- content/browser/gpu/gpu_data_manager_impl.h	(revision 136164)
+++ content/browser/gpu/gpu_data_manager_impl.h	(working copy)
@@ -81,15 +81,6 @@
   // If use-gl switch is osmesa or any, return true.
   bool UseGLIsOSMesaOrAny();
 
-  // Merges the second GPUInfo object with the first.
-  // If it's the same GPU, i.e., device id and vendor id are the same, then
-  // copy over the fields that are not set yet and ignore the rest.
-  // If it's a different GPU, then reset and copy over everything.
-  // Return true if something changes that may affect blacklisting; currently
-  // they are device_id, vendor_id, driver_vendor, driver_version, driver_date,
-  // and gl_renderer.
-  static bool Merge(content::GPUInfo* object, const content::GPUInfo& other);

[Ken Russell (switch to Gerrit), 2012/05/10 01:11:09]

Was removing this method intentional? If the GPU process fails to collect GPU
information and manages to send back an empty GPUInfo to the browser process, it
looks like the browser process will always overwrite its possibly better
information. Is that what was happening on Optimus machines before this CL? Is
the new behavior better or worse than the earlier behavior?

[Zhenyao Mo, 2012/05/10 21:55:32]

The removal of this Merge function is on purpose.  It's very easy to miss this
function when we add new fields to the GPUInfo, and the optimization we lose
without Merge is ignorable (we always re-run blacklist logic when we launch GPU
process).

However, you are right, I failed to consider the case where GPU process side
info collection fails.  Fixed in the new CL.

-
   // Try to switch to software rendering, if possible and necessary.
   void EnableSoftwareRenderingIfNecessary();