[Chromecast] Use reduced user agent after enabled by chromium

When chromium feature |blink::features::kReduceUserAgent| is enabled,
use the chromium reduced user agent.

Test: Print the user agent with |blink::features::kReduceUserAgent|
disabled and enabled (see b/191670403 comment #29).
Also passed internal CQ.

Bug: b/191670403
Change-Id: I7b12c08214ce73c719d7cd47c99571fc2c724ed1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3140633
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Reviewed-by: Mike Taylor <miketaylr@chromium.org>
Reviewed-by: Sean Topping <seantopping@chromium.org>
Commit-Queue: Guohui Deng <guohuideng@chromium.org>
Cr-Commit-Position: refs/heads/main@{#921265}

diff --git a/chromecast/common/DEPS b/chromecast/common/DEPS
index 63ba4c4..b5e06a12 100644
--- a/chromecast/common/DEPS
+++ b/chromecast/common/DEPS

@@ -16,7 +16,7 @@
   "+net/url_request/redirect_info.h",
   "+services/network/public/cpp",
   "+services/service_manager/public/cpp",
-  "+third_party/blink/public/common/loader/url_loader_throttle.h",
+  "+third_party/blink/public/common",
   "+ui/accessibility",
   "+ui/base",
   "+ui/gfx",