chore: Use HttpJsonClientCallImpl in main branch

Author: lqiu96

gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/HttpJsonClientCallImpl.java

@@ -46,7 +46,6 @@
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Nullable;
 
@@ -122,11 +121,6 @@ final class HttpJsonClientCallImpl<RequestT, ResponseT>
   @GuardedBy("lock")
   private volatile boolean closed;
 
-  // Store the timeout future created by the deadline schedule executor. The future
-  // can be cancelled if a response has been received before the timeout.
-  @GuardedBy("lock")
-  private ScheduledFuture<?> timeoutFuture;
-
   HttpJsonClientCallImpl(
       ApiMethodDescriptor<RequestT, ResponseT> methodDescriptor,
       String endpoint,
@@ -173,20 +167,16 @@ public void start(Listener<ResponseT> responseListener, HttpJsonMetadata request
       Preconditions.checkState(this.listener == null, "The call is already started");
       this.listener = responseListener;
       this.requestHeaders = requestHeaders;
+    }
 
-      // Use the timeout duration value instead of calculating the future Instant
-      // Only schedule the deadline if the RPC timeout has been set in the RetrySettings
-      Duration timeout = callOptions.getTimeout();
-      if (timeout != null) {
-        // The future timeout value is guaranteed to not be a negative value as the
-        // RetryAlgorithm will not retry
-        long timeoutMs = timeout.toMillis();
-        // Assign the scheduled future so that it can be cancelled if the timeout task
-        // is not needed (response received prior to timeout)
-        timeoutFuture =
-            this.deadlineCancellationExecutor.schedule(
-                this::timeout, timeoutMs, TimeUnit.MILLISECONDS);
-      }
+    // Use the timeout duration value instead of calculating the future Instant
+    // Only schedule the deadline if the RPC timeout has been set in the RetrySettings
+    Duration timeout = callOptions.getTimeout();
+    if (timeout != null) {
+      // The future timeout value is guaranteed to not be a negative value as the
+      // RetryAlgorithm will not retry
+      long timeoutMs = timeout.toMillis();
+      this.deadlineCancellationExecutor.schedule(this::timeout, timeoutMs, TimeUnit.MILLISECONDS);
     }
   }
 
@@ -440,14 +430,6 @@ private void close(
         return;
       }
       closed = true;
-
-      // Cancel the timeout future if there is a timeout task created
-      if (timeoutFuture != null) {
-        // timeout() invokes close(), but cancelling a completed task should no-op
-        timeoutFuture.cancel(true);
-        timeoutFuture = null;
-      }
-
       // Best effort task cancellation (to not be confused with task's thread interruption).
       // If the task is in blocking I/O waiting for the server response, it will keep waiting for
       // the response from the server, but once response is received the task will exit silently.