Temporarily disable feed component to fix debug build

Failing due to too many classes in the main dex list.

TBR=fgorski

Bug: 820361
Change-Id: I11f0f913467a77751d267bd51e58210043d666d3
Reviewed-on: https://chromium-review.googlesource.com/956115Reviewed-by: agrieve <agrieve@chromium.org>
Commit-Queue: agrieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542137}

components/feed/features.gni

@@ -3,5 +3,7 @@
 # found in the LICENSE file.
 
 declare_args() {
-  enable_feed_in_chrome = is_android
+  # TODO(agrieve): Re-enable for is_android once multidex issue is resolved:
+  #     https://crbug.com/820361
+  enable_feed_in_chrome = false
 }