Linux: don't try and read shmmax in the sandbox.

base/sys_info.h

Index: base/sys_info.h
diff --git a/base/sys_info.h b/base/sys_info.h
index 581720d77feeddc4a4d512d37398fe07413f25eb..5469da545111832fa3cea84d6cf7c158220d02f9 100644
--- a/base/sys_info.h
+++ b/base/sys_info.h
@@ -65,6 +65,11 @@ class SysInfo {
   // allocate.
   static size_t VMAllocationGranularity();
 
+#if defined(OS_LINUX)
+  // Returns the maximum SysV shared memory segment size.
+  static size_t MaxSharedMemorySize();
+#endif
+
 #if defined(OS_CHROMEOS)
   // Returns the name of the version entry we wish to look up in the
   // Linux Standard Base release information file.