Store ninja file deps from PackageVarContext in the config

Store ninja file deps from ExistentPathForSource on a
PackageVarContext in the config instead of the PackageContext, as
the PackageContext may be shared between multiple tests running
in parallel.

Test: all soong tests
Change-Id: Ib1809a4dd4a82696e0fe48a87eac21a44684ecb5
diff --git a/android/ninja_deps.go b/android/ninja_deps.go
new file mode 100644
index 0000000..2f442d5
--- /dev/null
+++ b/android/ninja_deps.go
@@ -0,0 +1,43 @@
+// Copyright 2020 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 android
+
+import "sort"
+
+func (c *config) addNinjaFileDeps(deps ...string) {
+	for _, dep := range deps {
+		c.ninjaFileDepsSet.Store(dep, true)
+	}
+}
+
+func (c *config) ninjaFileDeps() []string {
+	var deps []string
+	c.ninjaFileDepsSet.Range(func(key, value interface{}) bool {
+		deps = append(deps, key.(string))
+		return true
+	})
+	sort.Strings(deps)
+	return deps
+}
+
+func ninjaDepsSingletonFactory() Singleton {
+	return &ninjaDepsSingleton{}
+}
+
+type ninjaDepsSingleton struct{}
+
+func (ninjaDepsSingleton) GenerateBuildActions(ctx SingletonContext) {
+	ctx.AddNinjaFileDeps(ctx.Config().ninjaFileDeps()...)
+}