Add -lrt flag to enable the usage of clock_gettime. Enable RawCodec for ChromeOS

gyp/codec.gyp

Index: gyp/codec.gyp
diff --git a/gyp/codec.gyp b/gyp/codec.gyp
index a445ff04e1a6ee234a0c2bb98016e6da330a5f96..e96aaed9d5a5b9d04226298c506bc96724678b1d 100644
--- a/gyp/codec.gyp
+++ b/gyp/codec.gyp
@@ -135,6 +135,11 @@
             'OTHER_CPLUSPLUSFLAGS': ['-fexceptions'],
           },
         }],
+        ['skia_os == "chromeos"', {
+          'link_settings': {
+            'libraries': ['-lrt', ],
+          },
+        }],
       ],
     },
   ],