[GPU] Get GPU process running on the mac...

gpu/command_buffer/common/cmd_buffer_common.cc

Index: gpu/command_buffer/common/cmd_buffer_common.cc
===================================================================
--- gpu/command_buffer/common/cmd_buffer_common.cc	(revision 37920)
+++ gpu/command_buffer/common/cmd_buffer_common.cc	(working copy)
@@ -8,8 +8,10 @@
 #include "gpu/command_buffer/common/cmd_buffer_common.h"
 
 namespace gpu {
-const int32 CommandHeader::kMaxSize = (1 << 21) - 1;
-
+#if !defined(OS_WIN)
+// gcc needs this to link, but MSVC requires it not be present
+const int32 CommandHeader::kMaxSize;
+#endif
 namespace cmd {
 
 const char* GetCommandName(CommandId command_id) {