Revert "Fixing mojo dependencies for blink/modules/indexeddb"

This reverts commit 41516e5f08b986042d5a5f92063c67fa1c750d8d.

Reason for revert: At least one build failed with a missing header file so this may have made the build flaky. Reverting while investigating/fixing.

Original change's description:
> Fixing mojo dependencies for blink/modules/indexeddb
> 
> This splits the mojo code in two. Once small chunk of helper classes that
> are mojo wrapped, and some high level code that is allowed to use mojo
> itself.
> 
> This CL also makes it allowed and possible to use modules_export.h in
> mojo types that map to code in blink/modules.
> 
> Without this patch gn check --check-generated reports errors like
> the ones below:
> 
> ERROR at //out/Default/gen/third_party/blink/public/mojom/indexeddb/indexeddb.mojom-blink-forward.h:24:11: Include not allowed.
> -#include "third_party/blink/renderer/modules/modules_export.h"
>           ^--------------------------------------------------
> It is not in any dependency of
>   //third_party/blink/public/mojom:mojom_modules_blink
> The include file is in the target(s):
>   //third_party/blink/renderer/modules:modules
> which should somehow be reachable.
> ------------------------------------------------
> ERROR at //out/Default/gen/third_party/blink/public/mojom/indexeddb/indexeddb.mojom-blink.h:55:11: Include not allowed.
> #include "third_party/blink/renderer/modules/indexeddb/idb_key_path.h"
>           ^----------------------------------------------------------
> It is not in any dependency of
>   //third_party/blink/public/mojom:mojom_modules_blink
> The include file is in the target(s):
>   //third_party/blink/renderer/modules/indexeddb:indexeddb
> which should somehow be reachable.
> 
> Bug: 938893
> Change-Id: I0cd9bfb502fa4290a21e61f686b6095455eb4e86
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1547696
> Reviewed-by: Daniel Cheng <dcheng@chromium.org>
> Commit-Queue: Daniel Bratell <bratell@opera.com>
> Cr-Commit-Position: refs/heads/master@{#647200}

TBR=cmp@chromium.org,dcheng@chromium.org,bratell@opera.com

Change-Id: I72b84bd4aa18648a13311bef1a9a44a3780eeed3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 938893
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1550445
Reviewed-by: Daniel Bratell <bratell@opera.com>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#647249}
4 files changed