SF: Add utility class for dumpsys formatting

The Dumper class automates stringifying (a minimal set of types for now)
and indenting.

Bug: 241285876
Test: dumpsys SurfaceFlinger --displays
Change-Id: I5581cd9cb4235e2c710e303b6ab634847554cc30
diff --git a/services/surfaceflinger/Display/DisplaySnapshot.cpp b/services/surfaceflinger/Display/DisplaySnapshot.cpp
index b4f104a..fca3a3d 100644
--- a/services/surfaceflinger/Display/DisplaySnapshot.cpp
+++ b/services/surfaceflinger/Display/DisplaySnapshot.cpp
@@ -41,18 +41,11 @@
             .transform(&ftl::to_key<DisplayModes>);
 }
 
-void DisplaySnapshot::dump(std::string& out) const {
-    using namespace std::string_literals;
+void DisplaySnapshot::dump(utils::Dumper& dumper) const {
+    using namespace std::string_view_literals;
 
-    out += "   connectionType="s;
-    out += ftl::enum_string(mConnectionType);
-
-    out += "\n   deviceProductInfo="s;
-    if (mDeviceProductInfo) {
-        mDeviceProductInfo->dump(out);
-    } else {
-        out += "{}"s;
-    }
+    dumper.dump("connectionType"sv, ftl::enum_string(mConnectionType));
+    dumper.dump("deviceProductInfo"sv, mDeviceProductInfo);
 }
 
 } // namespace android::display