impl(o11y): address review comment about call options

Author: diegomarquezp

sdk-platform-java/gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/HttpJsonCallContext.java

@@ -608,9 +608,10 @@ public ApiTracer getTracer() {
   public HttpJsonCallContext withTracer(@Nonnull ApiTracer newTracer) {
     Preconditions.checkNotNull(newTracer);
 
+    HttpJsonCallOptions newOptions = callOptions.toBuilder().setTracer(newTracer).build();
     return new HttpJsonCallContext(
         this.channel,
-        this.callOptions,
+        newOptions,
         this.timeout,
         this.streamWaitTimeout,
         this.streamIdleTimeout,

sdk-platform-java/gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/HttpJsonClientCalls.java

@@ -77,9 +77,6 @@ public static <RequestT, ResponseT> HttpJsonClientCall<RequestT, ResponseT> newC
     httpJsonContext.validateUniverseDomain();
 
     HttpJsonCallOptions callOptions = httpJsonContext.getCallOptions();
-    if (httpJsonContext.getTracer() != null) {
-      callOptions = callOptions.toBuilder().setTracer(httpJsonContext.getTracer()).build();
-    }
 
     // TODO: add headers interceptor logic
     return httpJsonContext.getChannel().newCall(methodDescriptor, callOptions);

sdk-platform-java/gax-java/gax-httpjson/src/test/java/com/google/api/gax/httpjson/HttpJsonClientCallsTest.java

@@ -93,9 +93,7 @@ void setUp() throws IOException {
   @Test
   void testValidUniverseDomain() {
     HttpJsonClientCalls.newCall(descriptor, callContext);
-    HttpJsonCallOptions expectedCallOptions =
-        callOptions.toBuilder().setTracer(callContext.getTracer()).build();
-    Mockito.verify(mockChannel, Mockito.times(1)).newCall(descriptor, expectedCallOptions);
+    Mockito.verify(mockChannel, Mockito.times(1)).newCall(descriptor, callOptions);
   }
 
   // This test is when the universe domain does not match