Prepare for --incompatible_use_toolchain_providers_in_java_common (#241)

See bazelbuild/bazel#7186,
grpc/grpc-java@c637527#diff-01b2f0c554164246dfe4fb696d181c9c

WORKSPACE

@@ -29,6 +29,7 @@ http_archive(
         "//third_party/io_grpc_grpc_java:054def3c63.patch",
         "//third_party/io_grpc_grpc_java:0959a846c8.patch",
         "//third_party/io_grpc_grpc_java:952a767b9c.patch",
+        "//third_party/io_grpc_grpc_java:c63752789e.patch",
     ],
     sha256 = "f5d0bdebc2a50d0e28f0d228d6c35081d3e973e6159f2695aa5c8c7f93d1e4d6",
     strip_prefix = "grpc-java-1.19.0",
@@ -41,19 +42,19 @@ grpc_java_repositories()
 
 http_archive(
     name = "googleapis",
+    build_file = "@build_buildfarm//:BUILD.googleapis",
     sha256 = "7b6ea252f0b8fb5cd722f45feb83e115b689909bbb6a393a873b6cbad4ceae1d",
-    url = "https://github.com/googleapis/googleapis/archive/143084a2624b6591ee1f9d23e7f5241856642f4d.zip",
     strip_prefix = "googleapis-143084a2624b6591ee1f9d23e7f5241856642f4d",
-    build_file = "@build_buildfarm//:BUILD.googleapis",
+    url = "https://github.com/googleapis/googleapis/archive/143084a2624b6591ee1f9d23e7f5241856642f4d.zip",
 )
 
 # The API that we implement.
 http_archive(
     name = "remote_apis",
+    build_file = "@build_buildfarm//:BUILD.remote_apis",
     sha256 = "6f22ba09356f8dbecb87ba03cacf147939f77fef1c9cfaffb3826691f3686e9b",
-    url = "https://github.com/bazelbuild/remote-apis/archive/cfe8e540cbb424e3ebc649ddcbc91190f70e23a6.zip",
     strip_prefix = "remote-apis-cfe8e540cbb424e3ebc649ddcbc91190f70e23a6",
-    build_file = "@build_buildfarm//:BUILD.remote_apis",
+    url = "https://github.com/bazelbuild/remote-apis/archive/cfe8e540cbb424e3ebc649ddcbc91190f70e23a6.zip",
 )
 
 load("//3rdparty:workspace.bzl", "maven_dependencies")
@@ -75,7 +76,6 @@ http_archive(
 )
 
 load("@io_bazel_rules_docker//container:container.bzl", "container_pull")
-
 load(
     "@io_bazel_rules_docker//java:image.bzl",
     _java_image_repos = "repositories",
@@ -84,8 +84,8 @@ load(
 _java_image_repos()
 
 container_pull(
-  name = "java_base",
-  registry = "gcr.io",
-  repository = "distroless/java",
-  digest = "sha256:8c1769cb253bdecc257470f7fba05446a55b70805fa686f227a11655a90dfe9e",
+    name = "java_base",
+    digest = "sha256:8c1769cb253bdecc257470f7fba05446a55b70805fa686f227a11655a90dfe9e",
+    registry = "gcr.io",
+    repository = "distroless/java",
 )

third_party/io_grpc_grpc_java/c63752789e.patch

@@ -0,0 +1,38 @@
+From c63752789e61dd44120dbafcc59f6c12d72d652f Mon Sep 17 00:00:00 2001
+From: Eric Anderson <ejona@google.com>
+Date: Thu, 7 Mar 2019 16:22:54 -0800
+Subject: [PATCH] java_grpc_library.bzl: Pre-migrate for Bazel
+ incompatible_use_toolchain_providers_in_java_common
+
+This doesn't actually yet work with
+--incompatible_use_toolchain_providers_in_java_common, as Bazel 0.23 didn't
+include enough pieces. But this will work in 0.24 with the flag flipped. In
+both cases it will continue working if the flag is not specified.
+
+See https://github.com/grpc/grpc-java/issues/5383#issuecomment-470357965 and
+https://github.com/bazelbuild/bazel/issues/7186
+---
+ java_grpc_library.bzl | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/java_grpc_library.bzl b/java_grpc_library.bzl
+index 4601d4d78c..ff8abd422a 100644
+--- a/java_grpc_library.bzl
++++ b/java_grpc_library.bzl
+@@ -1,3 +1,5 @@
++load("@bazel_tools//tools/jdk:toolchain_utils.bzl", "find_java_runtime_toolchain", "find_java_toolchain")
++
+ # "repository" here is for Bazel builds that span multiple WORKSPACES.
+ def _path_ignoring_repository(f):
+     if len(f.owner.workspace_root) == 0:
+@@ -40,8 +42,8 @@ def _java_rpc_library_impl(ctx):
+
+     java_info = java_common.compile(
+         ctx,
+-        java_toolchain = ctx.attr._java_toolchain,
+-        host_javabase = ctx.attr._host_javabase,
++        java_toolchain = find_java_toolchain(ctx, ctx.attr._java_toolchain),
++        host_javabase = find_java_runtime_toolchain(ctx, ctx.attr._host_javabase),
+         source_jars = [srcjar],
+         output_source_jar = ctx.outputs.srcjar,
+         output = ctx.outputs.jar,