Add experimental, non-snapshotted V8 extras

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index fae41a7361336fcc27883cfd0e9a65ddeb0c9b92..4c9241fd805531bb73bcdb6fe686bdfef472038d 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -367,6 +367,36 @@ action("js2c_extras") {
   }
 }
 
+action("js2c_experimental_extras") {
+  visibility = [ ":*" ]  # Only targets in this file can depend on this.
+
+  script = "tools/js2c.py"
+
+  # The script depends on this other script, this rule causes a rebuild if it
+  # changes.
+  inputs = [ "tools/jsmin.py" ]
+
+  sources = v8_experimental_extra_library_files
+
+  outputs = [
+    "$target_gen_dir/experimental-extras-libraries.cc",
+  ]
+
+  args = [
+           rebase_path("$target_gen_dir/experimental-extras-libraries.cc",
+                       root_build_dir),
+           "EXPERIMENTAL_EXTRAS",
+         ] + rebase_path(sources, root_build_dir)
+
+  if (v8_use_external_startup_data) {
+    outputs += [ "$target_gen_dir/libraries_experimental_extras.bin" ]
+    args += [
+      "--startup_blob",
+      rebase_path("$target_gen_dir/libraries_experimental_extras.bin", root_build_dir),
+    ]
+  }
+}
+
 action("d8_js2c") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
 
@@ -394,6 +424,7 @@ if (v8_use_external_startup_data) {
       ":js2c_code_stubs",
       ":js2c_experimental",
       ":js2c_extras",
+      ":js2c_experimental_extras",
     ]
 
     sources = [
@@ -401,6 +432,7 @@ if (v8_use_external_startup_data) {
       "$target_gen_dir/libraries_code_stub.bin",
       "$target_gen_dir/libraries_experimental.bin",
       "$target_gen_dir/libraries_extras.bin",
+      "$target_gen_dir/libraries_experimental_extras.bin",
     ]
 
     outputs = [
@@ -487,6 +519,7 @@ source_set("v8_nosnapshot") {
     ":js2c_code_stubs",
     ":js2c_experimental",
     ":js2c_extras",
+    ":js2c_experimental_extras",
     ":v8_base",
   ]
 
@@ -495,6 +528,7 @@ source_set("v8_nosnapshot") {
     "$target_gen_dir/code-stub-libraries.cc",
     "$target_gen_dir/experimental-libraries.cc",
     "$target_gen_dir/extras-libraries.cc",
+    "$target_gen_dir/experimental-extras-libraries.cc",
     "src/snapshot/snapshot-empty.cc",
   ]
 
@@ -520,6 +554,7 @@ source_set("v8_snapshot") {
     ":js2c_code_stubs",
     ":js2c_experimental",
     ":js2c_extras",
+    ":js2c_experimental_extras",
     ":v8_base",
   ]
   public_deps = [
@@ -533,6 +568,7 @@ source_set("v8_snapshot") {
     "$target_gen_dir/code-stub-libraries.cc",
     "$target_gen_dir/experimental-libraries.cc",
     "$target_gen_dir/extras-libraries.cc",
+    "$target_gen_dir/experimental-extras-libraries.cc",
     "$target_gen_dir/snapshot.cc",
   ]
 
@@ -554,6 +590,7 @@ if (v8_use_external_startup_data) {
       ":js2c_code_stubs",
       ":js2c_experimental",
       ":js2c_extras",
+      ":js2c_experimental_extras",
       ":v8_base",
     ]
     public_deps = [