Revert "[chromecast] Add bindings_manager_cast target for Android build"

This reverts commit d08541bb.

Reason for revert: In favor of focusing on supporting Linux build for now.

Original change's description:
> [chromecast] Add bindings_manager_cast target for Android build
>
> Previously, bindings_manager_cast target was guarded by is_linux. This
> should be available for all non-fuchsia builds.
>
> Bug: internal b/141398875
> Test: CQ
> Change-Id: I21d95c65040956dd4446eff61dbd50acbb3f4e20
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1815949
> Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
> Reviewed-by: Yuchen Liu <yucliu@chromium.org>
> Commit-Queue: Jiawei Li <lijiawei@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#699041}

TBR=kmarshall@chromium.org,yucliu@chromium.org,lijiawei@chromium.org

Change-Id: I6d42eb1f3bfa79904cc5c0b39576e47c409ff30f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: internal b/141398875
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1818465
Commit-Queue: Yuchen Liu <yucliu@chromium.org>
Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Auto-Submit: Jiawei Li <lijiawei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699058}

chromecast/bindings/BUILD.gn

@@ -56,7 +56,7 @@ if (is_fuchsia) {
   }
 }
 
-if (is_linux || is_android) {
+if (is_linux) {
   source_set("bindings_manager_cast") {
     sources = [
       "bindings_manager_cast.cc",
@@ -111,7 +111,7 @@ if (is_linux || is_android) {
 source_set("browsertests") {
   testonly = true
   deps = []
-  if (is_linux || is_android) {
+  if (is_linux) {
     deps += [ "//chromecast/bindings:browsertests_cast" ]
   }
 }