Change the default of --api-overloaded-method-order from source to signature

Needed to match the behavior that AndroidX expects.

Bug: 285312164
Test: ./gradlew
      m checkapi
Change-Id: I89289f949f73420418e54eb143f42ec123d79bd5
diff --git a/src/main/java/com/android/tools/metalava/Options.kt b/src/main/java/com/android/tools/metalava/Options.kt
index 635dd00..8718d6b 100644
--- a/src/main/java/com/android/tools/metalava/Options.kt
+++ b/src/main/java/com/android/tools/metalava/Options.kt
@@ -445,7 +445,7 @@
      * Determines how overloaded methods, i.e. methods with the same name, are ordered in signature
      * files.
      */
-    var apiOverloadedMethodOrder: OverloadedMethodOrder = OverloadedMethodOrder.SOURCE
+    var apiOverloadedMethodOrder: OverloadedMethodOrder = OverloadedMethodOrder.SIGNATURE
 
     /** Like [apiFile], but with JDiff xml format. */
     var apiXmlFile: File? = null
@@ -2192,7 +2192,7 @@
             "$ARG_DEX_API <file>", "Generate a DEX signature descriptor file listing the APIs",
             "$ARG_REMOVED_API <file>", "Generate a signature descriptor file for APIs that have been removed",
             "$ARG_API_OVERLOADED_METHOD_ORDER <source|signature>",
-            "Specifies the order of overloaded methods in signature files (default `source`). " +
+            "Specifies the order of overloaded methods in signature files (default `signature`). " +
                 "Applies to the contents of the files specified on $ARG_API and $ARG_REMOVED_API. " +
                 "`$ARG_API_OVERLOADED_METHOD_ORDER source` will preserve the order in which they appear in the source files. " +
                 "`$ARG_API_OVERLOADED_METHOD_ORDER signature` will sort them based on their signature.",
diff --git a/src/test/java/com/android/tools/metalava/ApiFileTest.kt b/src/test/java/com/android/tools/metalava/ApiFileTest.kt
index 0b6ffa1..80670c2 100644
--- a/src/test/java/com/android/tools/metalava/ApiFileTest.kt
+++ b/src/test/java/com/android/tools/metalava/ApiFileTest.kt
@@ -3881,8 +3881,7 @@
         check(
             signatureSources = arrayOf(source1, source2),
             api = expected,
-            // Use the default overloaded method order when no command line option is supplied.
-            overloadedMethodOrder = null,
+            overloadedMethodOrder = Options.OverloadedMethodOrder.SOURCE,
             format = FileFormat.V2,
         )
     }
diff --git a/src/test/java/com/android/tools/metalava/OptionsTest.kt b/src/test/java/com/android/tools/metalava/OptionsTest.kt
index 1973436..480b868 100644
--- a/src/test/java/com/android/tools/metalava/OptionsTest.kt
+++ b/src/test/java/com/android/tools/metalava/OptionsTest.kt
@@ -188,7 +188,7 @@
                                              Generate a signature descriptor file for APIs that have been removed
 --api-overloaded-method-order <source|signature>
                                              Specifies the order of overloaded methods in signature files (default
-                                             `source`). Applies to the contents of the files specified on --api and
+                                             `signature`). Applies to the contents of the files specified on --api and
                                              --removed-api. `--api-overloaded-method-order source` will preserve the
                                              order in which they appear in the source files.
                                              `--api-overloaded-method-order signature` will sort them based on their