Remind ourselves why @IgnoreUnderRavenwood.

To aid future auditing, and determining which tests might be
ready to enable, support adding blockedBy and/or reason to
the @IgnoreUnderRavenwood annotation.  Apply to most of our
existing usages in tests.

Bug: 292141694
Test: atest-dev CtsUtilTestCasesRavenwood CtsProtoTestCasesRavenwood CtsOsTestCasesRavenwood CtsContentTestCasesRavenwood CtsDatabaseTestCasesRavenwood
Change-Id: I8807c44013f8f029844de641b43804ecf3766acb

ravenwood/junit-src/android/platform/test/annotations/IgnoreUnderRavenwood.java

@@ -22,12 +22,30 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 /**
- * THIS ANNOTATION IS EXPERIMENTAL. REACH OUT TO g/ravenwood BEFORE USING IT, OR YOU HAVE ANY
- * QUESTIONS ABOUT IT.
+ * Test methods marked with this annotation are quietly ignored when running under a Ravenwood test
+ * environment. The test continues to execute normally under all other non-Ravenwood test
+ * environments.
+ *
+ * This annotation only takes effect when the containing class has a {@code
+ * RavenwoodRule} configured. Ignoring is accomplished by throwing an {@code org.junit
+ * .AssumptionViolatedException} which test infrastructure treats as being ignored.
+ *
+ * Developers are encouraged to use either the {@code blockedBy} and/or {@code reason} arguments
+ * to document why a test is being ignored, to aid in future audits of tests that are candidates
+ * to be enabled.
  *
  * @hide
  */
 @Target(ElementType.METHOD)
 @Retention(RetentionPolicy.RUNTIME)
 public @interface IgnoreUnderRavenwood {
+    /**
+     * One or more classes that aren't yet supported by Ravenwood, which this test depends on.
+     */
+    Class<?>[] blockedBy() default {};
+
+    /**
+     * General free-form description of why this test is being ignored.
+     */
+    String reason() default "";
 }