guava: disavow VisibleForTesting

Johannes and I invented this class in the early days of Blaze,
and in hindsight it was clearly a mistake; it encourages self-deception.
This change adds a comment discouraging its further use.

RELNOTES=n/a

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=314347092

Author: adonovan

android/guava/src/com/google/common/annotations/VisibleForTesting.java

@@ -18,6 +18,13 @@
  * Annotates a program element that exists, or is more widely visible than otherwise necessary, only
  * for use in test code.
  *
+ * <p><b>Do not use this interface</b> for public or protected declarations: it is a fig leaf for
+ * bad design, and it does not prevent anyone from using the declaration---and experience has shown
+ * that they will. If the method breaks the encapsulation of its class, then its internal
+ * representation will be hard to change. Instead, use <a
+ * href="http://errorprone.info/bugpattern/RestrictedApiChecker">RestrictedApiChecker</a>, which
+ * enforces fine-grained visibility policies.
+ *
  * @author Johannes Henkel
  */
 @GwtCompatible

guava/src/com/google/common/annotations/VisibleForTesting.java

@@ -18,6 +18,13 @@
  * Annotates a program element that exists, or is more widely visible than otherwise necessary, only
  * for use in test code.
  *
+ * <p><b>Do not use this interface</b> for public or protected declarations: it is a fig leaf for
+ * bad design, and it does not prevent anyone from using the declaration---and experience has shown
+ * that they will. If the method breaks the encapsulation of its class, then its internal
+ * representation will be hard to change. Instead, use <a
+ * href="http://errorprone.info/bugpattern/RestrictedApiChecker">RestrictedApiChecker</a>, which
+ * enforces fine-grained visibility policies.
+ *
  * @author Johannes Henkel
  */
 @GwtCompatible