[chrome-releases] Add auto method (#469)

Based on https://chromiumdash.appspot.com API.

src/chrome-releases.py

@@ -0,0 +1,20 @@
+import re
+
+from common import dates, http
+from common.releasedata import ProductData, config_from_argv
+
+"""Fetches versions from https://chromiumdash.appspot.com API."""
+
+FIRST_AVAILABLE_VERSION = 7
+DATE_REGEX = re.compile(r'Stable release date:')
+
+config = config_from_argv()
+with ProductData(config.product) as product_data:
+    latest_release = int(product_data.get_latest_release().name())
+    n_available_releases = latest_release - FIRST_AVAILABLE_VERSION
+
+    releases = http.fetch_json(f"{config.url}?offset=-{n_available_releases}&n={n_available_releases + 1}")
+    for json_release in releases.get("mstones", []):
+        release = product_data.get_release(str(json_release["mstone"]))
+        release_date = dates.parse_datetime(json_release["stable_date"])
+        release.set_release_date(release_date)

src/common/releasedata.py

@@ -160,6 +160,9 @@ class ProductData:
         self.updated = True
         return self.releases[release_name]
 
+    def get_latest_release(self) -> ProductRelease | None:
+        return next(iter(self.releases.values()), None)  # assuming releases are sorted in descending order
+
     def remove_release(self, release_name: str) -> None:
         if release_name not in self.releases:
             logging.warning(f"release {release_name} cannot be removed as it does not exist for {self}")