Revert of Fix //content/plugin ax_enums gn build flake (patchset #1 id:1 of https://codereview.chromium.org/1343883003/ )
Revert of Fix //content/plugin ax_enums gn build flake (patchset #1 id:1 of https://codereview.chromium.org/1343883003/ )

Reason for revert:
This broke Win x64 GN builds:

ERROR Dependency cycle:
  //content:content ->
  //content/public/plugin:plugin_sources ->
  //content/plugin:plugin ->
  //content/public/common:common ->
  //content:content

Original issue's description:
> Fix //content/plugin ax_enums gn build flake
>
> Flake observerd with target_os="android" and enable_plugins=true:
> //content/plugin/plugin_thread.cc ends up including the generated
> ax_enums header so make it depend on it.
>
> BUG=
>
> Committed: https://crrev.com/d050925ac8f0324186269b1f10c0a8a9d24fab40
> Cr-Commit-Position: refs/heads/master@{#348918}

TBR=ananta@chromium.org,jam@chromium.org,tsniatowski@opera.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1339173003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#348927}

CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend