[Reland] Have content/DEPS depend on components/variations.

This originally failed because it caused checkdeps to fail.
https://ci.chromium.org/p/chromium/builders/ci/linux-trusty-rel/15902?

A bug was filed since the CQ didn't catch this: http://crbug/1129491.

This CL addresses that issue by only changing DEPS under src/content.
The checkdeps errors were a result of my changes to a couple files under
src/components/.*/content/DEPS.

Original change:
https://chromium-review.googlesource.com/c/chromium/src/+/2414842

Original message:
Have content/DEPS depend on components/variations.

content/ already depends on components/variations in multiple places;
see the bug for more details.

This will also eliminate the need to add additional variations-related
dependencies in content/renderer/DEPS and content/browser/DEPS, e.g.
https://chromium-review.googlesource.com/c/chromium/src/+/2411489/2.

Bug: 1129078
Change-Id: I426cb4a67a50919930af7e8b8c239b80176d676f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417066Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#808764}

content/DEPS

@@ -26,6 +26,7 @@ include_rules = [
 
   "+components/services/filesystem",
   "+components/services/font/public",
+  "+components/variations",
 
   "+crypto",
   "+grit/blink_resources.h",

content/browser/DEPS

@@ -34,9 +34,6 @@ include_rules = [
   "+components/tracing",
   "+components/ukm",
   "+components/url_formatter",
-  "+components/variations/variations_client.h",
-  "+components/variations/variations_ids_provider.h",
-  "+components/variations/net",
   "+components/viz",
   "+components/web_package",
   "+components/cbor",

content/child/DEPS

@@ -2,7 +2,6 @@ include_rules = [
   # Allow inclusion of specific components that we depend on.
   # See comment in content/DEPS for which components are allowed.
   "+components/tracing",
-  "+components/variations/child_process_field_trial_syncer.h",
   "+components/webcrypto",
   "+components/services/font/public",
 

content/renderer/DEPS

@@ -9,7 +9,6 @@ include_rules = [
   "+components/metrics:single_sample_metrics",
   "+components/payments",
   "+components/url_formatter",
-  "+components/variations/net",
   "+components/viz/client",
   "+components/viz/common",
   # *********************************** NOTE ***********************************