Ship use new hash function

Reviewed By: okelepko

Differential Revision: D54265549

fbshipit-source-id: 8fc9e33843b5e2a5dabf6a7d833e8572bc644df6

fbcore/src/main/java/com/facebook/common/callercontext/ContextChain.java

@@ -46,7 +46,6 @@ public class ContextChain implements Parcelable {
   private String mSerializedNodeString;
 
   private static boolean sUseConcurrentHashMap = false;
-  private static boolean sUseNewHashFunction = false;
 
   public ContextChain(
       final String tag,
@@ -102,10 +101,6 @@ public static void setUseConcurrentHashMap(boolean useConcurrentHashMap) {
     sUseConcurrentHashMap = useConcurrentHashMap;
   }
 
-  public static void setUseNewHashFunction(boolean useNewHashFunction) {
-    sUseNewHashFunction = useNewHashFunction;
-  }
-
   public String getName() {
     return mName;
   }
@@ -195,13 +190,7 @@ public boolean equals(@Nullable Object obj) {
 
   @Override
   public int hashCode() {
-    if (sUseNewHashFunction) {
-      return Objects.hash(mParent, getNodeString());
-    } else {
-      int result = super.hashCode();
-      result = 31 * result + (getNodeString().hashCode());
-      return result;
-    }
+    return Objects.hash(mParent, getNodeString());
   }
 
   @Override