Reland "Make //third_party/fontconfig explicitly depend on //third_party:freetype_harfbuzz."

This reverts commit 9ef757a8.

Reason for revert: is again needed after https://chromium-review.googlesource.com/c/chromium/src/+/1362457 was reverted

Original change's description:
> Revert "Make //third_party/fontconfig explicitly depend on //third_party:freetype_harfbuzz."
> 
> This reverts commit 0baa5bdf.
> 
> Reason for revert: is not needed after https://chromium-review.googlesource.com/c/chromium/src/+/1362457
> 
> Original change's description:
> > Make //third_party/fontconfig explicitly depend on //third_party:freetype_harfbuzz.
> > 
> > Bug: 911836
> > Change-Id: Ia76687b3cb8d329792e5ef0310faee93d05344f2
> > Reviewed-on: https://chromium-review.googlesource.com/c/1361725
> > Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
> > Commit-Queue: Max Moroz <mmoroz@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#613792}
> 
> TBR=bungeman@chromium.org,mmoroz@chromium.org,thomasanderson@chromium.org
> 
> # Not skipping CQ checks because original CL landed > 1 day ago.
> 
> Bug: 911836
> Change-Id: Ibc4c88faadd5c1e603fc0f26ce956c282909798e
> Reviewed-on: https://chromium-review.googlesource.com/c/1365083
> Reviewed-by: Max Moroz <mmoroz@chromium.org>
> Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
> Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#614534}

TBR=bungeman@chromium.org,mmoroz@chromium.org,thomasanderson@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 911836
Change-Id: Id09d7c0394e8c5eb445aa19ba5a62f8fa251ecb0
Reviewed-on: https://chromium-review.googlesource.com/c/1371885Reviewed-by: Friedrich Horschig [CET] <fhorschig@chromium.org>
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Commit-Queue: Friedrich Horschig [CET] <fhorschig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615545}

third_party/fontconfig/BUILD.gn

@@ -76,6 +76,9 @@ if (use_bundled_fontconfig) {
     configs += [ "//build/config/compiler:no_chromium_code" ]
 
     public_configs = [ ":fontconfig_config" ]
+    public_deps = [
+      "//third_party:freetype_harfbuzz",
+    ]
 
     if (is_clang) {
       cflags = [