Revert "Revert "GN rtc_* templates: Set default visibility to webrtc_root + "/*"""

This reverts commit c73e1f437889d882cbf2987f7fb3a029a6150613.

Reason for revert: 
The problem with failed deps in chrome content/renderer had already been fixed in https://webrtc-review.googlesource.com/c/src/+/38660

Original change's description:
> Revert "GN rtc_* templates: Set default visibility to webrtc_root + "/*""
> 
> This reverts commit 588c548657b3ddf76e7b3f241263eef7f5799f16.
> 
> Reason for revert: 
> 
> Breaks Chrome FYI:
> 
> /b/c/b/Linux_Builder/src/buildtools/linux64/gn gen //out/Release --check
>   -> returned 1
> ERROR at //build/split_static_library.gni:12:5: Dependency not allowed.
>     static_library(target_name) {
>     ^----------------------------
> The item //content/renderer:renderer
> can not depend on //third_party/webrtc/media:rtc_internal_video_codecs
> because it is not in //third_party/webrtc/media:rtc_internal_video_codecs's visibility list: [
>   //third_party/webrtc/*
>   //third_party/webrtc_overrides/*
> ]
> 
>  https://logs.chromium.org/v/?s=chromium%2Fbb%2Fchromium.webrtc.fyi%2FLinux_Builder%2F23560%2F%2B%2Frecipes%2Fsteps%2Fgenerate_build_files%2F0%2Fstdout
> 
> Original change's description:
> > GN rtc_* templates: Set default visibility to webrtc_root + "/*"
> > 
> > This means that by default, targets are visible to everything under
> > the WebRTC root, but not visible to anything else.
> > 
> > API targets are manually tagged with visibility "*", so that targets
> > outside the WebRTC tree can see them.
> > 
> > BUG=webrtc:8254
> > 
> > Change-Id: Icdbee6e0d22d93240ff2fb530c8f9dc48e351509
> > Reviewed-on: https://webrtc-review.googlesource.com/24140
> > Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
> > Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
> > Cr-Commit-Position: refs/heads/master@{#21548}
> 
> TBR=mbonadei@webrtc.org,kwiberg@webrtc.org
> 
> Change-Id: I06620ce3d6f67482935c22efa231dd6cab91625a
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: webrtc:8254
> Reviewed-on: https://webrtc-review.googlesource.com/38760
> Reviewed-by: Per Kjellander <perkj@webrtc.org>
> Commit-Queue: Per Kjellander <perkj@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#21555}

TBR=mbonadei@webrtc.org,kwiberg@webrtc.org,perkj@webrtc.org

Change-Id: I6f720078ce21bd172e0a6471bae8c4c011e4a657
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:8254
Reviewed-on: https://webrtc-review.googlesource.com/38860
Reviewed-by: Per Kjellander <perkj@webrtc.org>
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21558}
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index cc475f7..479f67f 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -64,6 +64,7 @@
 }
 
 source_set("protobuf_utils") {
+  visibility = [ "*" ]
   sources = [
     "protobuf_utils.h",
   ]
@@ -81,6 +82,7 @@
 }
 
 rtc_source_set("rtc_base_approved") {
+  visibility = [ "*" ]
   public_deps = [
     ":rtc_base_approved_generic",
   ]
@@ -377,6 +379,7 @@
 }
 
 rtc_source_set("rtc_task_queue") {
+  visibility = [ "*" ]
   deps = [
     ":rtc_base_approved",
   ]
@@ -405,6 +408,7 @@
 }
 
 rtc_source_set("rtc_task_queue_impl") {
+  visibility = [ "*" ]
   deps = [
     ":checks",
     ":rtc_base_approved",
@@ -506,6 +510,7 @@
 }
 
 rtc_static_library("rtc_base") {
+  visibility = [ "*" ]
   public_deps = [
     ":rtc_base_generic",
   ]
@@ -789,6 +794,7 @@
 }
 
 rtc_source_set("gtest_prod") {
+  visibility = [ "*" ]
   sources = [
     "gtest_prod_util.h",
   ]
@@ -984,6 +990,7 @@
   }
 
   rtc_source_set("rtc_task_queue_unittests") {
+    visibility = [ "*" ]
     testonly = true
 
     sources = [