Add Feed DEPS roll helper script to update proto references

Change-Id: I3d10b7e233015b291681200cda2e42c7706571d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1880276
Commit-Queue: Carlos Knippschild <carlosk@chromium.org>
Reviewed-by: Dan H <harringtond@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709300}

third_party/feed/fix_protos.sh

+#!/bin/bash
+# Copyright 2019 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Fixes protobufs references in proto_sources.gni.
+PROTO_SOURCES="third_party/feed/proto_sources.gni"
+if ! [[ -f "$PROTO_SOURCES" ]]; then
+  echo "Cannot locate: $PROTO_SOURCES"
+  exit 1
+fi
+
+# Exit when any command fails.
+set -e
+
+TEMP_FILE="third_party/feed/temp_proto.txt"
+if [[ -f "$TEMP_FILE" ]]; then
+	rm $TEMP_FILE
+fi
+sed -i '/proto".$/d' $PROTO_SOURCES
+find third_party/feed/src | grep \\.proto$ | env LC_COLLATE=en_US.ASCII sort | sed 's/^third_party.feed.\(.*\)/  "\1",/g' > $TEMP_FILE
+# It seems OK to have double quotes here so that $TEMP_FILE gets expanded.
+sed -i "/\[/r $TEMP_FILE" $PROTO_SOURCES
+rm $TEMP_FILE
+echo "proto_sources.gni updated successfully"