Split SYSTEMSERVERCLASSPATH entries from platform_bootclasspath.

Boot jars are different to system server jars at build level, due to
added complexity of dexpreopt. As a logical separation add a new
classpath fragment type and split existing classpaths.proto generation
into relevant pieces.

Bug: 180105615
Test: m && launch_cvd; atest CtsClasspathsTestCases
Change-Id: I88bec09fc920166ffd0092faef980754ddeb6593
diff --git a/java/systemserver_classpath_fragment.go b/java/systemserver_classpath_fragment.go
new file mode 100644
index 0000000..3f8a083
--- /dev/null
+++ b/java/systemserver_classpath_fragment.go
@@ -0,0 +1,50 @@
+// Copyright 2021 Google Inc. All rights reserved.
+//
+// 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.
+
+package java
+
+import (
+	"android/soong/android"
+)
+
+func init() {
+	registerSystemserverClasspathBuildComponents(android.InitRegistrationContext)
+}
+
+func registerSystemserverClasspathBuildComponents(ctx android.RegistrationContext) {
+	// TODO(satayev): add systemserver_classpath_fragment module
+	ctx.RegisterModuleType("platform_systemserverclasspath", platformSystemServerClasspathFactory)
+}
+
+type platformSystemServerClasspathModule struct {
+	android.ModuleBase
+
+	ClasspathFragmentBase
+}
+
+func platformSystemServerClasspathFactory() android.Module {
+	m := &platformSystemServerClasspathModule{}
+	initClasspathFragment(m, SYSTEMSERVERCLASSPATH)
+	android.InitAndroidArchModule(m, android.DeviceSupported, android.MultilibCommon)
+	return m
+}
+
+func (b *platformSystemServerClasspathModule) AndroidMkEntries() (entries []android.AndroidMkEntries) {
+	return b.classpathFragmentBase().androidMkEntries()
+}
+
+func (b *platformSystemServerClasspathModule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	// TODO(satayev): split apex jars into separate configs.
+	b.classpathFragmentBase().generateClasspathProtoBuildActions(ctx)
+}