DO NOT MERGE: Add tradefed_java_library_host

Add a module type for tradefed libraries that causes an additional
copy to be installed at out/host/linux-x86/tradefed.

Bug: 143908003
Exclude merging into *-plus-aosp branches, since they already include the change.
Merged-In: I670345494abbad80dacab54471e635abfae3b3b3
Merged-In: I1cb25bbd5823a14f1a9428d58827677eff22ec7e
Change-Id: I55bca53e02588827374896ef87d58f3f4bdc48c7
(cherry picked from commit f0f2e2cf79558569c227e8d96a784d9c0679814a)
(cherry picked from commit cba45b28925b2fb3ebbd9e281a185de0d2b8b0c7)
diff --git a/Android.bp b/Android.bp
index 2692b1b..2f5343e 100644
--- a/Android.bp
+++ b/Android.bp
@@ -281,6 +281,7 @@
         "java/support_libraries.go",
         "java/system_modules.go",
         "java/testing.go",
+        "java/tradefed.go",
     ],
     testSrcs: [
         "java/app_test.go",
diff --git a/java/java.go b/java/java.go
index 9ac38c9..6bfdfee 100644
--- a/java/java.go
+++ b/java/java.go
@@ -1453,6 +1453,8 @@
 
 type Library struct {
 	Module
+
+	InstallMixin func(ctx android.ModuleContext, installPath android.Path) (extraInstallDeps android.Paths)
 }
 
 func shouldUncompressDex(ctx android.ModuleContext, dexpreopter *dexpreopter) bool {
@@ -1482,8 +1484,12 @@
 	j.compile(ctx)
 
 	if (Bool(j.properties.Installable) || ctx.Host()) && !android.DirectlyInAnyApex(ctx, ctx.ModuleName()) {
+		var extraInstallDeps android.Paths
+		if j.InstallMixin != nil {
+			extraInstallDeps = j.InstallMixin(ctx, j.outputFile)
+		}
 		j.installFile = ctx.InstallFile(android.PathForModuleInstall(ctx, "framework"),
-			ctx.ModuleName()+".jar", j.outputFile)
+			ctx.ModuleName()+".jar", j.outputFile, extraInstallDeps...)
 	}
 }
 
diff --git a/java/tradefed.go b/java/tradefed.go
new file mode 100644
index 0000000..ebbdec1
--- /dev/null
+++ b/java/tradefed.go
@@ -0,0 +1,37 @@
+// Copyright 2019 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() {
+	android.RegisterModuleType("tradefed_java_library_host", tradefedJavaLibraryFactory)
+}
+
+// tradefed_java_library_factory wraps java_library and installs an additional
+// copy of the output jar to $HOST_OUT/tradefed.
+func tradefedJavaLibraryFactory() android.Module {
+	module := LibraryHostFactory().(*Library)
+	module.InstallMixin = tradefedJavaLibraryInstall
+	return module
+}
+
+func tradefedJavaLibraryInstall(ctx android.ModuleContext, path android.Path) android.Paths {
+	installedPath := ctx.InstallFile(android.PathForModuleInstall(ctx, "tradefed"),
+		ctx.ModuleName()+".jar", path)
+	return android.Paths{installedPath}
+}