graphics: move ComposerBase to HAL support library

Create android.hardware.graphics.composer@2.1-hal and add
ComposerHal, which is heavily based on ComposerBase, to it.

There are two bigger TODOs.  One is to remove the concept of
"clients" from the class and the other is to remove hwcomposer2.h
dependency.

Test: boots and VTS
Change-Id: I37b4fb3ae2239bf11aa87a56d1e2ebfe0b8c6b54
diff --git a/graphics/composer/2.1/utils/hal/Android.bp b/graphics/composer/2.1/utils/hal/Android.bp
new file mode 100644
index 0000000..35ddc0a
--- /dev/null
+++ b/graphics/composer/2.1/utils/hal/Android.bp
@@ -0,0 +1,29 @@
+//
+// Copyright (C) 2018 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+cc_library_headers {
+    name: "android.hardware.graphics.composer@2.1-hal",
+    defaults: ["hidl_defaults"],
+    vendor_available: true,
+    shared_libs: [
+        "android.hardware.graphics.composer@2.1",
+        "libhardware", // TODO remove hwcomposer2.h dependency
+    ],
+    export_shared_lib_headers: [
+        "android.hardware.graphics.composer@2.1",
+        "libhardware",
+    ],
+    export_include_dirs: ["include"],
+}