Add a default value and make it true for dagger & guice MapKey.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=89998087
diff --git a/extensions/multibindings/src/com/google/inject/multibindings/MapKey.java b/extensions/multibindings/src/com/google/inject/multibindings/MapKey.java
index bcb6a3b..2fc3374 100644
--- a/extensions/multibindings/src/com/google/inject/multibindings/MapKey.java
+++ b/extensions/multibindings/src/com/google/inject/multibindings/MapKey.java
@@ -54,5 +54,5 @@
    * instances will be the keys. If {@code unwrapValue} is true, the value() type of key type
    * annotation will be the key type for injected map and the value instances will be the keys.
    */
-  boolean unwrapValue();
+  boolean unwrapValue() default true;
 }