Update git submodules

* Update platform/external/perfetto from branch 'master'
  to 99fc76f4d62d3afd3dd40addc61b1795d2b3e4f2
  - Merge "Fix vm_test_utils.cc on NaCL."
  - Fix vm_test_utils.cc on NaCL.
    
    Make IsMapped always return true on NaCL to perfetto_test_support to
    compile there as mincore isn't available on NaCL.
    
    R=skyostil@google.com
    
    Change-Id: I81ce9e506b21b59af2d9fcf5a2143af6d8b3d068
1 file changed