Enable hwcomposer support only conditionally

src/anbox/qemu/boot_properties_message_processor.cpp

@@ -64,15 +64,17 @@ void BootPropertiesMessageProcessor::list_properties() {
         // Disable on-screen virtual keys as we can use the hardware keyboard
         "qemu.hw.mainkeys=1",
 
-        // To let surfaceflinger load our hwcomposer implementation we specify
-        // the correct subkey of the module here.
-        // "ro.hardware.hwcomposer=anbox",
-
         // Android has builtin detection (inside Zygote) for proper container
         // detection support
         "ro.boot.container=1",
     };
 
+    if (utils::is_env_set("USE_HWCOMPOSER")) {
+        // To let surfaceflinger load our hwcomposer implementation we specify
+        // the correct subkey of the module here.
+        properties.push_back("ro.hardware.hwcomposer=anbox");
+    }
+
     for (const auto &prop : properties) {
         send_header(prop.length());
         messenger_->send(prop.c_str(), prop.length());

src/anbox/utils.cpp

@@ -141,6 +141,10 @@ std::string get_env_value(const std::string &name, const std::string &default_va
     return std::string(value);
 }
 
+bool is_env_set(const std::string &name) {
+    return getenv(name.c_str()) != nullptr;
+}
+
 void ensure_paths(const std::vector<std::string> &paths) {
     for (const auto &path: paths) {
         if (!fs::is_directory(fs::path(path)))

src/anbox/utils.h

@@ -39,6 +39,7 @@ bool string_starts_with(const std::string &text, const std::string &prefix);
 std::string hex_dump(const uint8_t *data, uint32_t size);
 
 std::string get_env_value(const std::string &name, const std::string &default_value = "");
+bool is_env_set(const std::string &name);
 
 void ensure_paths(const std::vector<std::string> &paths);