Create an app snapshot of the Dart front end.

runtime/bin/BUILD.gn

Index: runtime/bin/BUILD.gn
diff --git a/runtime/bin/BUILD.gn b/runtime/bin/BUILD.gn
index c3140f0d76a31fff5b21c9b7677f6a0442628b11..91381cf35a77ffa65823c5dfdc32f2d11e3b7619 100644
--- a/runtime/bin/BUILD.gn
+++ b/runtime/bin/BUILD.gn
@@ -489,6 +489,40 @@ action("generate_snapshot_bin") {
   ]
 }
 
+action("generate_dfe_snapshot") {

[zra, 2017/01/26 20:55:00]

This should try to use the "application_snapshot" template here:

https://github.com/dart-lang/sdk/blob/master/utils/application_snapshot.gni#L9

If it's not a perfect fit, feel free to modify the template.

I also wonder if runtime/tools/kernel-service.dart and this rule should be moved
to //utils or //pkg to be closer to other things that we make app snapshots for.
Like, //pkg/kernel-service/BUILD.gn, and
//pkg/kernel-service/kernel-service.dart.

[Siggi Cherem (dart-lang), 2017/01/26 22:38:13]

DBC - I like the idea of moving this. Two small related suggestions:

 - consider renaming this script file so we follow the naming conventions we
have everywhere else (remove/replace the "-").

 - could this go under pkg/front_end/bin or pkg/front_end/tool?

I have a CL in progress to update kernel-service.dart to go through
pkg/front_end API (which today wraps dartk but in the future can use fasta). I'm
also fine waiting to do all those changes separately after this lands.

[rmacnak, 2017/01/26 23:48:45]

Change to application_snapshot template and moved to //utils/kernel-service.
Kept with kernel-service rather than kernel_service to avoid changing some names
inside the VM and consistency with the vm-service. Other can move it further
later if they feel it's important.

+  deps = [
+    "../bin:dart($host_toolchain)",
+  ]
+
+  package_map = rebase_path("../../.packages")
+  dfe_script = rebase_path("../tools/kernel-service.dart")
+  dfe_snapshot = "$root_out_dir/kernel-service.dart.snapshot"
+  training_script =
+      "file://" + rebase_path("../../pkg/compiler/lib/src/dart2js.dart")
+  dart_dir = get_label_info("../bin:dart($host_toolchain)", "root_out_dir")
+  dart_path = rebase_path("$dart_dir/dart")
+
+  inputs = [
+    package_map,
+    dfe_script,
+  ]
+
+  outputs = [
+    dfe_snapshot,
+  ]
+
+  script = rebase_path("../../build/gn_run_binary.py")
+  args = [
+    "exec_script",
+    dart_path,
+    "--snapshot=" + rebase_path(dfe_snapshot),
+    "--snapshot-kind=app-jit",
+    "--packages=" + package_map,
+    dfe_script,
+    training_script,
+  ]
+}
+
 action("generate_snapshot_file") {
   deps = [
     ":generate_snapshot_bin",
@@ -496,7 +530,7 @@ action("generate_snapshot_file") {
 
   snapshot_in_cc_file = "snapshot_in.cc"
   inputs = [
-    "../tools/create_snapshot_file.py",
+    "../tools/create_snapshot_cc.py",
     snapshot_in_cc_file,
     "$target_gen_dir/vm_isolate_snapshot.bin",
     "$target_gen_dir/isolate_snapshot.bin",
@@ -506,7 +540,7 @@ action("generate_snapshot_file") {
     output,
   ]
 
-  script = "../tools/create_snapshot_file.py"
+  script = "../tools/create_snapshot_cc.py"
   args = [
     "--vm_input_bin",
     rebase_path("$target_gen_dir/vm_isolate_snapshot.bin"),