Add an option '--depfile' to produce ninja-style depfile for the generated kernel. (#4704)
Add an option '--depfile' to produce ninja-style depfile for the generated kernel. (#4704)

* Add an option '--depfile' to produce ninja-style depfile for the generated kernel file.

* Use [program.uriToSource] as a source of dependencies.

jamesr/flutter_engine,devoncarew/engine,rmacnak-google/engine,chinmaygarde/sky_engine,jason-simmons/sky_engine,jason-simmons/sky_engine,cdotstout/sky_engine,cdotstout/sky_engine,devoncarew/engine,jason-simmons/sky_engine,Hixie/sky_engine,chinmaygarde/sky_engine,jamesr/flutter_engine,jason-simmons/flutter_engine,chinmaygarde/sky_engine,jamesr/flutter_engine,rmacnak-google/engine,krisgiesing/sky_engine,tvolkert/engine,devoncarew/sky_engine,cdotstout/sky_engine,jamesr/sky_engine,rmacnak-google/engine,chinmaygarde/flutter_engine,devoncarew/engine,krisgiesing/sky_engine,jason-simmons/sky_engine,jamesr/sky_engine,devoncarew/engine,cdotstout/sky_engine,Hixie/sky_engine,mikejurka/engine,chinmaygarde/sky_engine,mikejurka/engine,flutter/engine,jamesr/flutter_engine,Hixie/sky_engine,krisgiesing/sky_engine,flutter/engine,jason-simmons/flutter_engine,chinmaygarde/flutter_engine,jason-simmons/flutter_engine,devoncarew/sky_engine,jason-simmons/flutter_engine,tvolkert/engine,devoncarew/sky_engine,jamesr/flutter_engine,jamesr/flutter_engine,krisgiesing/sky_engine,devoncarew/engine,jamesr/sky_engine,krisgiesing/sky_engine,aam/engine,devoncarew/engine,mikejurka/engine,Hixie/sky_engine,mikejurka/engine,tvolkert/engine,jamesr/sky_engine,chinmaygarde/flutter_engine,aam/engine,aam/engine,devoncarew/engine,Hixie/sky_engine,flutter/engine,rmacnak-google/engine,jamesr/flutter_engine,jamesr/sky_engine,Hixie/sky_engine,mikejurka/engine,Hixie/sky_engine,rmacnak-google/engine,aam/engine,flutter/engine,chinmaygarde/flutter_engine,cdotstout/sky_engine,krisgiesing/sky_engine,cdotstout/sky_engine,tvolkert/engine,chinmaygarde/flutter_engine,jason-simmons/sky_engine,jamesr/sky_engine,devoncarew/sky_engine,mikejurka/engine,chinmaygarde/flutter_engine,Hixie/sky_engine,jamesr/flutter_engine,flutter/engine,aam/engine,chinmaygarde/flutter_engine,devoncarew/sky_engine,devoncarew/sky_engine,jason-simmons/sky_engine,aam/engine,mikejurka/engine,chinmaygarde/sky_engine,jason-simmons/flutter_engine,tvolkert/engine,aam/engine,jason-simmons/flutter_engine,krisgiesing/sky_engine,aam/engine,flutter/engine,jason-simmons/sky_engine,mikejurka/engine,devoncarew/sky_engine,chinmaygarde/sky_engine,cdotstout/sky_engine,jamesr/flutter_engine,jamesr/sky_engine,jason-simmons/flutter_engine,jason-simmons/flutter_engine,mikejurka/engine,tvolkert/engine,rmacnak-google/engine,chinmaygarde/sky_engine,flutter/engine,rmacnak-google/engine,flutter/engine,tvolkert/engine