Revert "Add an initial version of WebLayer."

This reverts commit c55da80.

Reason for revert: suspect causing compile failure on win-archive-rel.

Sample Build: https://ci.chromium.org/p/chromium/builders/ci/win32-archive-rel/4119

Sample Log: https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8904360639454286896/+/steps/compile/0/stdout

E.g.
[80569/83877] LINK weblayer_shell.exe weblayer_shell.exe.pdb
FAILED: weblayer_shell.exe weblayer_shell.exe.pdb
ninja -t msvc -e environment.x86 -- ../../third_party/llvm-build/Release+Asserts/bin/lld-link.exe /nologo /OUT:./weblayer_shell.exe /PDB:./weblayer_shell.exe.pdb @./weblayer_shell.exe.rsp
lld-link: error: undefined symbol: int __cdecl content::PpapiPluginMain(struct content::MainFunctionParams const &)
>>> referenced by obj/content/app/content_main_runner_both/content_main_runner_impl.obj:(struct content::MainFunction const *const `int __cdecl content::RunOtherNamedProcessTypeMain(class std::__1::basic_string<char, struct std::__1::char_traits<char>, class std::__1::allocator<char>> const &, struct content::MainFunctionParams const &, class content::ContentMainDelegate *)'::`2'::kMainFunctions)

lld-link: error: undefined symbol: int __cdecl content::PpapiBrokerMain(struct content::MainFunctionParams const &)
>>> referenced by obj/content/app/content_main_runner_both/content_main_runner_impl.obj:(struct content::MainFunction const *const `int __cdecl content::RunOtherNamedProcessTypeMain(class std::__1::basic_string<char, struct std::__1::char_traits<char>, class std::__1::allocator<char>> const &, struct content::MainFunctionParams const &, class content::ContentMainDelegate *)'::`2'::kMainFunctions)

Original change's description:
> Add an initial version of WebLayer.
> 
> This is based on part of the proposed API from go/weblayer-api. It currently only works on Windows and Linux.
> 
> weblayer/public is the public API. The includes to src/content are encapsulated in the implementation.
> 
> weblayer/shell is a simple demo.
> 
> Change-Id: Ibdd71d452e930f07fbb8209658cd64345eb9f384
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1766781
> Commit-Queue: John Abd-El-Malek <jam@chromium.org>
> Reviewed-by: Darin Fisher <darin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#689807}

TBR=jam@chromium.org,darin@chromium.org

Change-Id: I18b6066e7531a4c69abebefa738d05c614cc582b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1767452
Reviewed-by: Takashi Sakamoto <tasak@google.com>
Commit-Queue: Takashi Sakamoto <tasak@google.com>
Cr-Commit-Position: refs/heads/master@{#689816}

BUILD.gn

@@ -195,11 +195,6 @@ group("gn_all") {
     ]
   }
 
-  # TODO: add Android.
-  if (is_win || (is_linux && !is_chromeos)) {
-    deps += [ "//weblayer/shell:weblayer_shell" ]
-  }
-
   if (!is_ios && !is_android) {
     deps += [
       "//components/cronet:cronet_tests",

weblayer/README.md

@@ -1,30 +1,12 @@
 # WebLayer
 
-WebLayer is a high level embedding API to support building a browser.
-
-Unlike src/content, which is only concerned with a sandboxed multi-process web
-platform, WebLayer includes modern browser features and Google integration.
-It's the reusable version of Chrome, which might share some portions of the UI
-and also its support for all the modern HTML5 and browser features (e.g. UI for
-permissions, autofill, safe browsing etc...).
-
-While it's built on top of src/content, the expectation is that the API will
-hide the Content API.
+WebLayer is a high level embedding API to support building a browser. While it's
+built on top of src/content, the expectation is that the API will hide the
+Content API. WebLayer is envisioned to include support for all the modern HTML5
+and browser features (e.g. UI for permissions, autofill, safe browsing etc...).
 
 ## Resources and Documentation
 
 Mailing list: [weblayer-dev@chromium.org](https://groups.google.com/a/chromium.org/forum/#!forum/weblayer-dev)
 
 Bug tracker: [Internals>WebLayer](https://bugs.chromium.org/p/chromium/issues/list?can=2&q=component%3AInternals%3EWebLayer)
-
-## Directory Structure
-
-`public` the C++ and Java public API. These are the only files an app should use
-
-`shell` sample app
-
-`browser` internal code which runs in the browser process
-
-`common` internal code which runs in the browser and child processes
-
-`renderer` internal code which runs in the renderer process