Remove unused function parameter (#344)

Author: gregfenton

firestore/test.solution-counters.js

@@ -22,7 +22,7 @@ function createCounter(ref, num_shards) {
 // [END create_counter]
 
 // [START increment_counter]
-functionincrementCounter(db,ref,num_shards){
+functionincrementCounter(ref,num_shards){
 // Select a shard of the counter at random
 constshard_id=Math.floor(Math.random()*num_shards).toString();
 constshard_ref=ref.collection('shards').doc(shard_id);
@@ -67,15 +67,15 @@ describe("firestore-solution-counters", () => {
 // Create a counter, then increment it
 constref=db.collection('counters').doc();
 returncreateCounter(ref,10).then(()=>{
-returnincrementCounter(db,ref,10);
+returnincrementCounter(ref,10);
 });
 });
 
 it("should get the count of a counter",()=>{
 // Create a counter, increment it, then get the count
 constref=db.collection('counters').doc();
 returncreateCounter(ref,10).then(()=>{
-returnincrementCounter(db,ref,10);
+returnincrementCounter(ref,10);
 }).then(()=>{
 returngetCount(ref);
 });