WebUI: Replace vulcanize with polymer-bundler

chrome/browser/resources/md_history/BUILD.gn

 import("../vulcanize.gni")
 
 app_unbuilt = "app.vulcanized.unbuilt.html"
 lazy_load_unbuilt = "lazy_load.vulcanized.unbuilt.html"
 
 vulcanize("vulcanize_app") {
   host = "history"
-  html_in_file = "app.html"
-  html_out_file = app_unbuilt
+  html_in_files = [
+    "app.html",
+    "lazy_load.html",
+  ]
+  html_out_files = [
+    app_unbuilt,
+    lazy_load_unbuilt,
+  ]
 
   input = rebase_path(".", root_build_dir)
-  js_out_file = "app.crisper.js"
+  js_out_files = [
+    "app.crisper.js",
+    "lazy_load.crisper.js",
+  ]
 
   excludes = [
     "chrome://resources/html/util.html",
     "chrome://history/constants.html",
   ]
 
   deps = []
-}
-
-vulcanize("vulcanize_lazy_load") {
-  host = "history"
-  html_in_file = "lazy_load.html"
-  html_out_file = lazy_load_unbuilt
-
-  input = rebase_path(".", root_build_dir)
-  js_out_file = "lazy_load.crisper.js"
-  excludes = [
-    "chrome://resources/html/util.html",
-    "chrome://history/constants.html",
-    "chrome://history/app.html",
-  ]
-
-  deps = []
 }
 
 polymer_css_build("build") {

[calamity, 2017/07/19 06:15:33]

FYI, it should be possible to roll this into a single target now. This needed to
be a separate target so that both unbuilt targets would exist after their
separate runs, and then be fed in as dependencies.

Since there's only one step that does all files at once, we can trivially
serialize polymer_css_build in the vulcanize python script.

[dpapad, 2017/07/19 20:49:38]

Yes. I plan to merge this operation back into vulcanize_gn.py since it is not
needed as a separate operation anymore, but prefer to do this in a follow up CL
to keep this CL from getting even larger.

   input_files = [
     app_unbuilt,
     lazy_load_unbuilt,
   ]
   output_files = [
     "app.vulcanized.html",
     "lazy_load.vulcanized.html",
   ]
   deps = [
     ":vulcanize_app",
-    ":vulcanize_lazy_load",
   ]
 }