Return owned object from PropertyMap

To help keep track of object ownership, use smart pointers in
PropertyMap.

Bug: 163171599
Test: presubmit
Change-Id: I4194e6640c8b0e1ec0db9d9e65b3f6862d6f37d4
diff --git a/libs/input/PropertyMap.cpp b/libs/input/PropertyMap.cpp
index 4833eb9..a842166 100644
--- a/libs/input/PropertyMap.cpp
+++ b/libs/input/PropertyMap.cpp
@@ -107,23 +107,22 @@
     }
 }
 
-status_t PropertyMap::load(const String8& filename, PropertyMap** outMap) {
-    *outMap = nullptr;
+android::base::Result<std::unique_ptr<PropertyMap>> PropertyMap::load(const char* filename) {
+    std::unique_ptr<PropertyMap> outMap = std::make_unique<PropertyMap>();
+    if (outMap == nullptr) {
+        return android::base::Error(NO_MEMORY) << "Error allocating property map.";
+    }
 
-    Tokenizer* tokenizer;
-    status_t status = Tokenizer::open(filename, &tokenizer);
+    Tokenizer* rawTokenizer;
+    status_t status = Tokenizer::open(String8(filename), &rawTokenizer);
+    std::unique_ptr<Tokenizer> tokenizer(rawTokenizer);
     if (status) {
-        ALOGE("Error %d opening property file %s.", status, filename.string());
+        ALOGE("Error %d opening property file %s.", status, filename);
     } else {
-        PropertyMap* map = new PropertyMap();
-        if (!map) {
-            ALOGE("Error allocating property map.");
-            status = NO_MEMORY;
-        } else {
 #if DEBUG_PARSER_PERFORMANCE
             nsecs_t startTime = systemTime(SYSTEM_TIME_MONOTONIC);
 #endif
-            Parser parser(map, tokenizer);
+            Parser parser(outMap.get(), tokenizer.get());
             status = parser.parse();
 #if DEBUG_PARSER_PERFORMANCE
             nsecs_t elapsedTime = systemTime(SYSTEM_TIME_MONOTONIC) - startTime;
@@ -132,14 +131,10 @@
                   elapsedTime / 1000000.0);
 #endif
             if (status) {
-                delete map;
-            } else {
-                *outMap = map;
+                return android::base::Error(BAD_VALUE) << "Could not parse " << filename;
             }
-        }
-        delete tokenizer;
     }
-    return status;
+    return std::move(outMap);
 }
 
 // --- PropertyMap::Parser ---