Add atom for sdk extension tests

This atom will be logged from a test app in /product/app. It is
temporary, and will be removed after successful R test missions.

Bug: 148945438
Test: out/host/linux-x86/bin/statsd_testdrive \
          -p com.google.android.apps.internal.sdkext.testapp 354
Change-Id: Ic25d601bfdb6f84cb9963581213ee6d3300424ab

cmds/statsd/src/atoms.proto

@@ -391,6 +391,7 @@ message Atom {
         WifiHealthStatReported wifi_health_stat_reported = 251 [(module) = "wifi"];
         WifiFailureStatReported wifi_failure_stat_reported = 252 [(module) = "wifi"];
         WifiConnectionResultReported wifi_connection_result_reported = 253 [(module) = "wifi"];
+        SdkExtensionStatus sdk_extension_status = 354;
     }
 
     // Pulled events will start at field 10000.
@@ -8337,3 +8338,27 @@ message CellBroadcastMessageError {
     // Exception message (or log message) associated with the error (max 1000 chars)
     optional string exception_message = 2;
 }
+
+/**
+ * Logs when the SDK Extensions test app has polled the current version.
+ * This is atom ID 354.
+ *
+ * Logged from:
+ *   vendor/google_testing/integration/packages/apps/SdkExtensionsTestApp/
+ */
+message SdkExtensionStatus {
+    enum ApiCallStatus {
+        CALL_NOT_ATTEMPTED = 0;
+        CALL_SUCCESSFUL = 1;
+        CALL_FAILED = 2;
+    }
+
+    optional ApiCallStatus result = 1;
+
+    // The R extension version, i.e. android.os.ext.SdkExtension.getExtensionVersion(R).
+    optional int32 r_extension_version = 2;
+
+    // A number identifying which particular symbol's call failed, if any. 0 means no missing symbol.
+    // "Failed" here can mean a symbol that wasn't meant to be visible was, or the other way around.
+    optional int32 failed_call_symbol = 3;
+}