Add FeatureOverrides::toString()

Add FeatureOverrides::toString() to output a string representation of
the current FeatureOverrides values. This is required when implementing
Parcelable (in a later patch) as well as for 'cmd gpu featureOverrides'
(also coming in a later CL).

Bug: 372694741
Test: CQ
Test: Manual verification with later CLs
Flag: com.android.graphics.graphicsenv.flags.feature_overrides
Change-Id: I77ca945f173ae1ad5430670c87e46985189409cb

Author: timvpGoogle

libs/graphicsenv/Android.bp

@@ -41,6 +41,7 @@ cc_library_shared {
     ],
 
     srcs: [
+        "FeatureOverrides.cpp",
         "GpuStatsInfo.cpp",
         "GraphicsEnv.cpp",
         "IGpuService.cpp",

libs/graphicsenv/FeatureOverrides.cpp

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2025 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.
+ */
+
+#include <graphicsenv/FeatureOverrides.h>
+
+#include <android-base/stringprintf.h>
+
+namespace android {
+
+using base::StringAppendF;
+
+std::string FeatureConfig::toString() const {
+    std::string result;
+    StringAppendF(&result, "Feature: %s\n", mFeatureName.c_str());
+    StringAppendF(&result, "      Status: %s\n", mEnabled ? "enabled" : "disabled");
+
+    return result;
+}
+
+std::string FeatureOverrides::toString() const {
+    std::string result;
+    result.append("Global Features:\n");
+    for (auto& cfg : mGlobalFeatures) {
+        result.append("  " + cfg.toString());
+    }
+    result.append("\n");
+    result.append("Package Features:\n");
+    for (const auto& packageFeature : mPackageFeatures) {
+        result.append("  Package:");
+        StringAppendF(&result, " %s\n", packageFeature.first.c_str());
+        for (auto& cfg : packageFeature.second) {
+            result.append("    " + cfg.toString());
+        }
+    }
+
+    return result;
+}
+
+} // namespace android

libs/graphicsenv/include/graphicsenv/FeatureOverrides.h

@@ -27,6 +27,7 @@ class FeatureConfig {
     FeatureConfig() = default;
     FeatureConfig(const FeatureConfig&) = default;
     virtual ~FeatureConfig() = default;
+    std::string toString() const;
 
     std::string mFeatureName;
     bool mEnabled;
@@ -41,6 +42,7 @@ class FeatureOverrides {
     FeatureOverrides() = default;
     FeatureOverrides(const FeatureOverrides&) = default;
     virtual ~FeatureOverrides() = default;
+    std::string toString() const;
 
     std::vector<FeatureConfig> mGlobalFeatures;
     /* Key: Package Name, Value: Package's Feature Configs */