Add action to extract library names and versions

Issue: 268355217
Reviewed-on: #3490

cobalt/browser/BUILD.gn

@@ -161,6 +161,7 @@ static_library("browser") {
     "//cobalt/browser/metrics",
     "//cobalt/build:cobalt_build_id",
     "//cobalt/build:cobalt_build_info",
+    "//cobalt/build:cobalt_libraries",
     "//cobalt/cache",
     "//cobalt/configuration",
     "//cobalt/css_parser",

cobalt/build/BUILD.gn

@@ -23,3 +23,12 @@ action("cobalt_build_info") {
   outputs = [ "$root_gen_dir/build_info.json" ]
   args = [ rebase_path(outputs[0], root_build_dir) ]
 }
+
+action("cobalt_libraries") {
+  script = "libraries.py"
+  outputs = [ "$root_gen_dir/libraries.tsv" ]
+  args = [
+    rebase_path(outputs[0], root_build_dir),
+    rebase_path("//", root_build_dir),  # source root
+  ]
+}

cobalt/build/libraries.py

@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+"""Extract names and versions of imported libraries."""
+
+import os
+import subprocess
+import sys
+
+output_path = sys.argv[1]
+source_root = sys.argv[2]
+
+with open(output_path, 'w', encoding='utf-8') as out:
+  print('name\tversion', file=out)  # header
+  os.chdir(source_root)
+  args = ['git', 'ls-files', '--', '*/README.*']
+  p = subprocess.run(args, capture_output=True, text=True, check=True)
+  for f in [f for f in p.stdout.splitlines() if not f.endswith('template')]:
+    try:
+      with open(f, encoding='utf-8') as file:
+        name = None
+        version = None
+        for line in file.readlines():
+          if line.startswith('Name: '):
+            name = line[len('Name: '):].strip()
+          if line.startswith('Version: '):
+            version = line[len('Version: '):].strip()
+        if name and version:
+          print(name + '\t' + version, file=out)  # row
+    except UnicodeDecodeError:
+      pass