Switch the file-type pusher to invoke Ninja

chrome/browser/resources/safe_browsing/README.md

 # Behavior of Download File Types in Chrome
 
 This describes how to adjust file-type download behavior in
 Chrome including interactions with Safe Browsing. The metadata described
 here, and stored in `download_file_types.asciipb`, will be both baked into
 Chrome released and pushable to Chrome between releases (via
 `FileTypePolicies` class).  http://crbug.com/596555
 
 Rendered version of this file: https://chromium.googlesource.com/chromium/src/+/master/chrome/browser/resources/safe_browsing/README.md
 
 
 ## Procedure for adding/modifying file type(s)
   * **Edit** `download_file_types.asciipb` and update `histograms.xml`
   * Get it reviewed, **submit.**
   * **Push** it to all users via component update:
     * Wait 1-3 day for this to run on Canary to verify it doesn't crash Chrome.
-    * In a synced checkout, generate protos for all platforms:
-        * % `ninja -C out-gn/Debug
-         chrome/browser/resources/safe_browsing:make_all_file_types_protobuf`
-    * That will instruct you to run another command to push the files to GCS.
-      You must a member of chrome-file-type-policies-pushers@google.com to have
+    * In a synced checkout, run the following to generate protos for all
+      platforms and push them to GCS. Replace the arg with your build directory:
+        * % `chrome/browser/resources/safe_browsing/push_file_type_proto.py -d
+          out-gn/Debug`
+    * It will ask you to double check its actions before proceeding.  It will
+      fail if you're not a member of
+      `chrome-file-type-policies-pushers@google.com`, since that's required for
       access to the GCS bucket.
     * The Component Updater system will notice those files and push them to
       users withing ~6 hours. If not, contact `waffles@.`
 
 
 ## Guidelines for a DownloadFileType entry:
 See `download_file_types.proto` for all fields.
 
   * `extension`: (required) Value must be unique within the config. It should be
     lowercase ASCII and not contain a dot. If there _is_ a duplicate,
@@ skipping 71 matching lines @@
 
   * `sampled_ping_probability`: For what fraction of extended-reporting
     users' downloads with unknown extensions (or
     ping_setting=SAMPLED_PING) should we send light-pings? [0.0 .. 1.0]
 
   * `file_types`: The big list of all known file types. Keep them
      sorted by extension.
 
   * `default_file_type`: Settings used if a downloaded file is not in
     the above list. `extension` is ignored, but other settings are used.
-    The ping_setting should be SAMPLED_PING for all platforms. Only the
-    first platform_setting is used.
+    The ping_setting should be SAMPLED_PING for all platforms.