Refactor DependencyResolver a bit.

RELNOTES: None.
PiperOrigin-RevId: 227718701
diff --git a/src/main/java/com/google/devtools/build/lib/pkgcache/TargetEdgeObserver.java b/src/main/java/com/google/devtools/build/lib/pkgcache/TargetEdgeObserver.java
index 9e30d92..bf50ec3 100644
--- a/src/main/java/com/google/devtools/build/lib/pkgcache/TargetEdgeObserver.java
+++ b/src/main/java/com/google/devtools/build/lib/pkgcache/TargetEdgeObserver.java
@@ -45,8 +45,7 @@
    * @param to a label reference in the rule, which does not correspond to a valid target.
    * @param e the corresponding exception thrown
    */
-  void missingEdge(@Nullable Target target, Label to, NoSuchThingException e)
-      throws InterruptedException;
+  void missingEdge(@Nullable Target target, Label to, NoSuchThingException e);
 
   /**
    * Called when a node is discovered. May be called