Revert "Dynamically enable/disable packet coalecsing and test it"

This reverts commit 60ab7ef00ac0a988ee2672c636d946c964e6fa41.
diff --git a/include/grpc/grpc_cronet.h b/include/grpc/grpc_cronet.h
index 566c34a..295e0f5 100644
--- a/include/grpc/grpc_cronet.h
+++ b/include/grpc/grpc_cronet.h
@@ -44,8 +44,6 @@
     void *engine, const char *target, const grpc_channel_args *args,
     void *reserved);
 
-GRPCAPI void grpc_cronet_use_packet_coalescing(bool use_coalescing);
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/core/ext/transport/cronet/client/secure/cronet_channel_create.c b/src/core/ext/transport/cronet/client/secure/cronet_channel_create.c
index 2e40020..477cf07 100644
--- a/src/core/ext/transport/cronet/client/secure/cronet_channel_create.c
+++ b/src/core/ext/transport/cronet/client/secure/cronet_channel_create.c
@@ -51,8 +51,6 @@
 
 extern grpc_transport_vtable grpc_cronet_vtable;
 
-bool grpc_cronet_packet_coalescing_enabled = true;
-
 GRPCAPI grpc_channel *grpc_cronet_secure_channel_create(
     void *engine, const char *target, const grpc_channel_args *args,
     void *reserved) {
@@ -69,7 +67,3 @@
   return grpc_channel_create(&exec_ctx, target, args,
                              GRPC_CLIENT_DIRECT_CHANNEL, (grpc_transport *)ct);
 }
-
-GRPCAPI void grpc_cronet_use_packet_coalescing(bool use_coalescing) {
-  grpc_cronet_packet_coalescing_enabled = use_coalescing;
-}
diff --git a/src/core/ext/transport/cronet/transport/cronet_transport.c b/src/core/ext/transport/cronet/transport/cronet_transport.c
index 5429eb3..447f3f3 100644
--- a/src/core/ext/transport/cronet/transport/cronet_transport.c
+++ b/src/core/ext/transport/cronet/transport/cronet_transport.c
@@ -61,8 +61,6 @@
 /* TODO (makdharma): Hook up into the wider tracing mechanism */
 int grpc_cronet_trace = 0;
 
-extern bool grpc_cronet_packet_coalescing_enabled;
-
 enum e_op_result {
   ACTION_TAKEN_WITH_CALLBACK,
   ACTION_TAKEN_NO_CALLBACK,
@@ -152,13 +150,12 @@
   bool state_callback_received[OP_NUM_OPS];
   bool fail_state;
   bool flush_read;
+#ifdef GRPC_CRONET_WITH_PACKET_COALESCING
   bool flush_cronet_when_ready;
   bool pending_write_for_trailer;
+#endif
   bool unprocessed_send_message;
   grpc_error *cancel_error;
-
-  /* Whether packet coalescing is enabled */
-  bool packet_coalescing_enabled;
   /* data structure for storing data coming from server */
   struct read_state rs;
   /* data structure for storing data going to the server */
@@ -428,10 +425,12 @@
   }
 /* Send the initial metadata on wire if there is no SEND_MESSAGE or
  * SEND_TRAILING_METADATA ops pending */
-  if (s->state.packet_coalescing_enabled && s->state.flush_cronet_when_ready) {
+#ifdef GRPC_CRONET_WITH_PACKET_COALESCING
+  if (s->state.flush_cronet_when_ready) {
     CRONET_LOG(GPR_DEBUG, "cronet_bidirectional_stream_flush (%p)", s->cbs);
     bidirectional_stream_flush(stream);
   }
+#endif
   gpr_mu_unlock(&s->mu);
   execute_from_storage(s);
 }
@@ -569,10 +568,10 @@
     CRONET_LOG(GPR_DEBUG, "bidirectional_stream_write (%p, 0)", s->cbs);
     s->state.state_callback_received[OP_SEND_MESSAGE] = false;
     bidirectional_stream_write(s->cbs, "", 0, true);
-    if (s->state.packet_coalescing_enabled) {
-      CRONET_LOG(GPR_DEBUG, "bidirectional_stream_flush (%p)", s->cbs);
-      bidirectional_stream_flush(s->cbs);
-    }
+#ifdef GRPC_CRONET_WITH_PACKET_COALESCING
+    CRONET_LOG(GPR_DEBUG, "bidirectional_stream_flush (%p)", s->cbs);
+    bidirectional_stream_flush(s->cbs);
+#endif
     s->state.state_op_done[OP_SEND_TRAILING_METADATA] = true;
 
     gpr_mu_unlock(&s->mu);
@@ -769,9 +768,11 @@
       result = false;
     /* we haven't got on_write_completed for the send yet */
     else if (stream_state->state_op_done[OP_SEND_MESSAGE] &&
-             !stream_state->state_callback_received[OP_SEND_MESSAGE] &&
-             !(stream_state->packet_coalescing_enabled &&
-               stream_state->pending_write_for_trailer))
+             !stream_state->state_callback_received[OP_SEND_MESSAGE]
+#ifdef GRPC_CRONET_WITH_PACKET_COALESCING
+             && !stream_state->pending_write_for_trailer
+#endif
+             )
       result = false;
   } else if (op_id == OP_CANCEL_ERROR) {
     /* already executed */
@@ -857,10 +858,10 @@
     s->cbs = bidirectional_stream_create(s->curr_ct.engine, s->curr_gs,
                                          &cronet_callbacks);
     CRONET_LOG(GPR_DEBUG, "%p = bidirectional_stream_create()", s->cbs);
-    if (stream_state->packet_coalescing_enabled) {
-      bidirectional_stream_disable_auto_flush(s->cbs, true);
-      bidirectional_stream_delay_request_headers_until_flush(s->cbs, true);
-    }
+#ifdef GRPC_CRONET_WITH_PACKET_COALESCING
+    bidirectional_stream_disable_auto_flush(s->cbs, true);
+    bidirectional_stream_delay_request_headers_until_flush(s->cbs, true);
+#endif
     char *url = NULL;
     const char *method = "POST";
     s->header_array.headers = NULL;
@@ -871,10 +872,11 @@
     CRONET_LOG(GPR_DEBUG, "bidirectional_stream_start(%p, %s)", s->cbs, url);
     bidirectional_stream_start(s->cbs, url, 0, method, &s->header_array, false);
     stream_state->state_op_done[OP_SEND_INITIAL_METADATA] = true;
-    if (stream_state->packet_coalescing_enabled && !stream_op->send_message &&
-        !stream_op->send_trailing_metadata) {
+#ifdef GRPC_CRONET_WITH_PACKET_COALESCING
+    if (!stream_op->send_message && !stream_op->send_trailing_metadata) {
       s->state.flush_cronet_when_ready = true;
     }
+#endif
     result = ACTION_TAKEN_WITH_CALLBACK;
   } else if (stream_op->send_message &&
              op_can_be_run(stream_op, stream_state, &oas->state,
@@ -911,18 +913,19 @@
         stream_state->state_callback_received[OP_SEND_MESSAGE] = false;
         bidirectional_stream_write(s->cbs, stream_state->ws.write_buffer,
                                    (int)write_buffer_size, false);
-        if (stream_state->packet_coalescing_enabled) {
-          if (!stream_op->send_trailing_metadata) {
-            CRONET_LOG(GPR_DEBUG, "bidirectional_stream_flush (%p)", s->cbs);
-            bidirectional_stream_flush(s->cbs);
-            result = ACTION_TAKEN_WITH_CALLBACK;
-          } else {
-            stream_state->pending_write_for_trailer = true;
-            result = ACTION_TAKEN_NO_CALLBACK;
-          }
-        } else {
+#ifdef GRPC_CRONET_WITH_PACKET_COALESCING
+        if (!stream_op->send_trailing_metadata) {
+          CRONET_LOG(GPR_DEBUG, "bidirectional_stream_flush (%p)",
+                     s->cbs);
+          bidirectional_stream_flush(s->cbs);
           result = ACTION_TAKEN_WITH_CALLBACK;
+        } else {
+          stream_state->pending_write_for_trailer = true;
+          result = ACTION_TAKEN_NO_CALLBACK;
         }
+#else
+        result = ACTION_TAKEN_WITH_CALLBACK;
+#endif
       } else {
         result = NO_ACTION_POSSIBLE;
       }
@@ -941,10 +944,10 @@
                  s->cbs);
       stream_state->state_callback_received[OP_SEND_MESSAGE] = false;
       bidirectional_stream_write(s->cbs, "", 0, true);
-      if (stream_state->packet_coalescing_enabled) {
-        CRONET_LOG(GPR_DEBUG, "bidirectional_stream_flush (%p)", s->cbs);
-        bidirectional_stream_flush(s->cbs);
-      }
+#ifdef GRPC_CRONET_WITH_PACKET_COALESCING
+      CRONET_LOG(GPR_DEBUG, "bidirectional_stream_flush (%p)", s->cbs);
+      bidirectional_stream_flush(s->cbs);
+#endif
       result = ACTION_TAKEN_WITH_CALLBACK;
     }
     stream_state->state_op_done[OP_SEND_TRAILING_METADATA] = true;
@@ -1173,9 +1176,10 @@
          sizeof(s->state.state_callback_received));
   s->state.fail_state = s->state.flush_read = false;
   s->state.cancel_error = NULL;
+#ifdef GRPC_CRONET_WITH_PACKET_COALESCING
   s->state.flush_cronet_when_ready = s->state.pending_write_for_trailer = false;
+#endif
   s->state.unprocessed_send_message = false;
-  s->state.packet_coalescing_enabled = grpc_cronet_packet_coalescing_enabled;
   gpr_mu_init(&s->mu);
   return 0;
 }
diff --git a/src/objective-c/tests/CronetUnitTests/CronetUnitTests.m b/src/objective-c/tests/CronetUnitTests/CronetUnitTests.m
index 9bbf3cd..dcd7f2f 100644
--- a/src/objective-c/tests/CronetUnitTests/CronetUnitTests.m
+++ b/src/objective-c/tests/CronetUnitTests/CronetUnitTests.m
@@ -269,9 +269,7 @@
   grpc_completion_queue_destroy(cq);
 }
 
-- (void)PacketCoalescing:(bool)use_coalescing {
-  grpc_cronet_use_packet_coalescing(use_coalescing);
-
+- (void)testPacketCoalescing {
   grpc_call *c;
   grpc_slice request_payload_slice =
   grpc_slice_from_copied_string("hello world");
@@ -381,7 +379,7 @@
     long len;
     bool coalesced = false;
     while ((len = SSL_read(ssl, buf, sizeof(buf))) > 0) {
-      gpr_log(GPR_DEBUG, "Read len: %ld", len);
+      NSLog(@"Read len: %ld", len);
 
       // Analyze the HTTP/2 frames in the same TLS PDU to identify if
       // coalescing is successful
@@ -406,7 +404,7 @@
       }
     }
 
-    XCTAssert(coalesced == use_coalescing);
+    XCTAssert(coalesced);
     SSL_free(ssl);
     SSL_CTX_free(ctx);
     close(s);
@@ -435,9 +433,4 @@
   grpc_completion_queue_destroy(cq);
 }
 
-- (void)testPacketCoalescing {
-  [self PacketCoalescing:false];
-  [self PacketCoalescing:true];
-}
-
 @end
diff --git a/src/objective-c/tests/Podfile b/src/objective-c/tests/Podfile
index 3760330..462c6a8 100644
--- a/src/objective-c/tests/Podfile
+++ b/src/objective-c/tests/Podfile
@@ -97,6 +97,7 @@
         # GPR_UNREACHABLE_CODE causes "Control may reach end of non-void
         # function" warning
         config.build_settings['GCC_WARN_ABOUT_RETURN_TYPE'] = 'NO'
+        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] = '$(inherited) COCOAPODS=1 GRPC_CRONET_WITH_PACKET_COALESCING=1'
       end
     end