Add missing 'break' statements to ppapi::proxy::NaClMessageScanner.

Two cases don't have breaks and fall through incorrectly. The first
may be responsible for issue http://crbug.com/370919.

BUG=370919

Review URL: https://codereview.chromium.org/307293002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@274408 0039d316-1c4b-4281-b951-d872f2087c98

ppapi/proxy/nacl_message_scanner.cc

@@ -392,6 +392,7 @@ void NaClMessageScanner::ScanUntrustedMessage(
                   PpapiHostMsg_FileIO_Close(
                       FileGrowth(trusted_max_written_offset, 0))));
         }
+        break;
       }
       case PpapiHostMsg_FileIO_SetLength::ID: {
         FileIOMap::iterator it = files_.find(params.pp_resource());
@@ -466,6 +467,7 @@ void NaClMessageScanner::ScanUntrustedMessage(
           delete fs_it->second;
           file_systems_.erase(fs_it);
         }
+        break;
       }
     }
   }