Reland "Have property_service create a serialized property_contexts file"

This reverts commit 9822f3c6cc5d85a462033cd545500bcc1c8b0927.

Bug: 36001741
Change-Id: I27dd391fc06a3c78e88a65c7931c84de1699f157
diff --git a/init/space_tokenizer.h b/init/space_tokenizer.h
new file mode 100644
index 0000000..e7e22c5
--- /dev/null
+++ b/init/space_tokenizer.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#ifndef _INIT_SPACE_TOKENIZER_H
+#define _INIT_SPACE_TOKENIZER_H
+
+namespace android {
+namespace init {
+
+class SpaceTokenizer {
+  public:
+    SpaceTokenizer(const std::string& string)
+        : string_(string), it_(string_.begin()), end_(string_.end()) {}
+
+    std::string GetNext() {
+        auto next = std::string();
+        while (it_ != end_ && !isspace(*it_)) {
+            next.push_back(*it_++);
+        }
+        while (it_ != end_ && isspace(*it_)) {
+            it_++;
+        }
+        return next;
+    }
+
+    std::string GetRemaining() { return std::string(it_, end_); }
+
+  private:
+    std::string string_;
+    std::string::const_iterator it_;
+    std::string::const_iterator end_;
+};
+
+}  // namespace init
+}  // namespace android
+
+#endif