Remove --harmony-modules flag and let embedder decide when modules are used

src/d8.cc

Index: src/d8.cc
diff --git a/src/d8.cc b/src/d8.cc
index c70ff42dc7b511692260b3b4e09f6269424ee430..d7e1b6ab06e6fa67638dd74f89434b5c78f6b404 100644
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -1983,8 +1983,6 @@ bool Shell::SetOptions(int argc, char* argv[]) {
 
   v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
 
-  bool enable_harmony_modules = false;

[Dan Ehrenberg, 2016/03/15 00:22:52]

Presumably there's no reasonable way to recover the module functionality at d8,
right? Because how would you collect the exports, and where would they go? Or
could we allow it but in a special mode where exports are banned?

[adamk, 2016/03/15 00:40:58]

Not sure what you mean...d8 does support modules. As per the comment below, it's
just handled in a different function. The following loads a file as a module:

d8 --module foo.js

At the moment imports don't work, but I have some basic tests in
mjsunit/harmony/modules.js

-
   // Set up isolated source groups.
   options.isolate_sources = new SourceGroup[options.num_isolates];
   SourceGroup* current = options.isolate_sources;
@@ -1997,7 +1995,6 @@ bool Shell::SetOptions(int argc, char* argv[]) {
       current->Begin(argv, i + 1);
     } else if (strcmp(str, "--module") == 0) {
       // Pass on to SourceGroup, which understands this option.
-      enable_harmony_modules = true;
     } else if (strncmp(argv[i], "--", 2) == 0) {
       printf("Warning: unknown flag %s.\nTry --help for options\n", argv[i]);
     } else if (strcmp(str, "-e") == 0 && i + 1 < argc) {
@@ -2013,10 +2010,6 @@ bool Shell::SetOptions(int argc, char* argv[]) {
     SetFlagsFromString("--nologfile_per_isolate");
   }
 
-  if (enable_harmony_modules) {
-    SetFlagsFromString("--harmony-modules");
-  }
-
   return true;
 }