Add RunfilesLibraryInfo provider

tools/BUILD

@@ -87,6 +87,7 @@ filegroup(
         "//tools/jdk:bzl_srcs",
         "//tools/osx:bzl_srcs",
         "//tools/python:bzl_srcs",
+        "//tools/runfiles:bzl_srcs",
         "//tools/sh:bzl_srcs",
         "//tools/test:bzl_srcs",
         "//tools/windows:bzl_srcs",

tools/runfiles/BUILD

@@ -11,6 +11,9 @@ filegroup(
 
 filegroup(
     name = "embedded_tools",
-    srcs = ["BUILD.tools"],
+    srcs = [
+        "BUILD.tools",
+        "runfiles.bzl",
+    ],
     visibility = ["//tools:__pkg__"],
 )

tools/runfiles/BUILD.tools

@@ -1,6 +1,12 @@
+package(default_visibility = ["//visibility:private"])
+
 java_library(
     name = "java-runfiles",
     deprecation = "Depend on @bazel_tools//tools/java/runfiles instead. This target will be deleted in Bazel 0.19.0",
-    visibility = ["//visibility:public"],
     exports = ["//tools/java/runfiles"],
 )
+
+filegroup(
+    name = "bzl_srcs",
+    srcs = ["runfiles.bzl"],
+)

tools/runfiles/runfiles.bzl

@@ -0,0 +1,9 @@
+RunfilesLibraryInfo = provider(
+    doc = """
+A marker for targets providing runfiles lookup functionality.
+
+Rules may choose to emit additional information required to locate runfiles at runtime if this provider is present on a direct dependency.
+
+Note: At this point, neither Bazel nor native rules check for the presence of this provider.
+""",
+)