[Bindings] Create and use V8 context snapshots

gin/BUILD.gn

Index: gin/BUILD.gn
diff --git a/gin/BUILD.gn b/gin/BUILD.gn
index 9d66473aa6f4982e5809788721838c60111fd24e..67959cfc771e929951790c763824221d7b293531 100644
--- a/gin/BUILD.gn
+++ b/gin/BUILD.gn
@@ -4,6 +4,7 @@
 
 import("//testing/test.gni")
 import("//v8/gni/v8.gni")
+import("//v8/snapshot_toolchain.gni")
 
 # This is depended upon from the browser DLL on Windows, where V8 is not used,
 # but features are enabled. This cannot depend on V8.
@@ -95,11 +96,11 @@ component("gin") {
   }
 
   defines = [ "GIN_IMPLEMENTATION" ]
-
   public_deps = [
     "//base",
     "//v8",
   ]
+
   deps = [
     ":gin_features",
     "//base/third_party/dynamic_annotations",
@@ -130,6 +131,56 @@ executable("gin_shell") {
   configs += [ "//v8:external_startup_data" ]
 }
 
+if (current_toolchain == v8_snapshot_toolchain) {
+  action("run_gin_blink_snapshot") {
+    script = "run.py"
+    exec = "$root_out_dir/gin_blink_snapshot"
+    output_file = "$root_out_dir/context_blob.bin"
+    output_path = rebase_path(output_file, root_build_dir)
+
+    args = [
+      rebase_path(exec, root_build_dir),
+      "--output_file=$output_path",
+    ]
+
+    outputs = [
+      output_file,
+    ]
+
+    deps = [
+      ":gin_blink_snapshot($v8_snapshot_toolchain)",
+    ]
+  }
+}
+
+# This config disables a link time optimization which merge some pointers,
+# but we must keep duplicated entries in external references for V8 snapshot.
+config("disable_icf") {
+  visibility = [ ":*" ]  # Only targets in this file can depend on this.
+  if (is_win) {
+    ldflags = [ "/OPT:NOICF" ]
+  } else if (is_posix && !is_mac) {
+    ldflags = [ "-Wl,--icf=none" ]
+  }
+}
+
+executable("gin_blink_snapshot") {
+  sources = [
+    "shell/gin_prepare_main.cc",
+  ]
+
+  deps = [
+    ":gin",
+    "//mojo/edk/system:system",
+    "//third_party/WebKit/public:blink",
+  ]
+
+  configs += [
+    "//v8:external_startup_data",
+    ":disable_icf",
+  ]
+}
+
 source_set("gin_test") {
   testonly = true
   sources = [