Create Bazel BUILD targets and Bazel rule for logtag file conversion.

Test: b build build/make/tools/...
Change-Id: I0a12e6cfff553a927f86381358a3f5f58fec0c75
diff --git a/tools/BUILD.bazel b/tools/BUILD.bazel
new file mode 100644
index 0000000..75b0de6
--- /dev/null
+++ b/tools/BUILD.bazel
@@ -0,0 +1,20 @@
+py_library(
+    name="event_log_tags",
+    srcs = ["event_log_tags.py"],
+)
+
+py_binary(
+    name="java-event-log-tags",
+    srcs=["java-event-log-tags.py"],
+    deps=[":event_log_tags"],
+    visibility = ["//visibility:public"],
+    python_version = "PY2",
+)
+
+py_binary(
+    name="merge-event-log-tags",
+    srcs=["merge-event-log-tags.py"],
+    deps=[":event_log_tags"],
+    visibility = ["//visibility:public"],
+    python_version = "PY2",
+)
diff --git a/tools/event_log_tags.bzl b/tools/event_log_tags.bzl
new file mode 100644
index 0000000..3766da4
--- /dev/null
+++ b/tools/event_log_tags.bzl
@@ -0,0 +1,47 @@
+"""Event log tags generation rule"""
+
+load("@bazel_skylib//lib:paths.bzl", "paths")
+load("@rules_android//rules:rules.bzl", "android_library")
+
+def _event_log_tags_impl(ctx):
+    out_files = []
+    for logtag_file in ctx.files.srcs:
+        out_filename = paths.replace_extension(logtag_file.basename, ".java")
+        out_file = ctx.actions.declare_file(out_filename)
+        out_files.append(out_file)
+        ctx.actions.run(
+            inputs = [logtag_file],
+            outputs = [out_file],
+            arguments = [
+                "-o",
+                out_file.path,
+                logtag_file.path,
+            ],
+            progress_message = "Generating Java logtag file from %s" % logtag_file.short_path,
+            executable = ctx.executable._logtag_to_java_tool,
+        )
+    return [DefaultInfo(files = depset(out_files))]
+
+_event_log_tags = rule(
+    implementation = _event_log_tags_impl,
+    attrs = {
+        "srcs": attr.label_list(allow_files = [".logtags"], mandatory = True),
+        "_logtag_to_java_tool": attr.label(
+            executable = True,
+            cfg = "exec",
+            allow_files = True,
+            default = Label("//build/make/tools:java-event-log-tags"),
+        ),
+    },
+)
+
+def event_log_tags(name, srcs):
+    _event_log_tags(
+        name = name + "_gen_logtags",
+        srcs = srcs,
+    )
+
+    android_library(
+        name = name,
+        srcs = [name + "_gen_logtags"],
+    )