URL: forward declare IPC::ParamTraits

Similarly to what is done for mojo traits, avoid depending to ipc
traits. The end result should be the same for chromium, but this
removes the dependency for Cronet.

Bug: 1395805
Change-Id: I8b9ef3ea98c21c92f5fe654430498aec2fe6c855
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4075568
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Stefano Duo <stefanoduo@google.com>
Cr-Commit-Position: refs/heads/main@{#1080303}

url/BUILD.gn

@@ -61,10 +61,7 @@ component("url") {
 
   public_deps = [ "//base" ]
 
-  deps = [
-    "//base/third_party/dynamic_annotations",
-    "//ipc:param_traits",
-  ]
+  deps = [ "//base/third_party/dynamic_annotations" ]
 
   if (is_win) {
     # Don't conflict with Windows' "url.dll".

url/origin.h

@@ -18,7 +18,6 @@
 #include "base/unguessable_token.h"
 #include "build/build_config.h"
 #include "build/buildflag.h"
-#include "ipc/ipc_param_traits.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
 #include "third_party/perfetto/include/perfetto/tracing/traced_value_forward.h"
 #include "url/scheme_host_port.h"
@@ -43,6 +42,11 @@ class SecurityOrigin;
 class SecurityOriginTest;
 }  // namespace blink
 
+namespace IPC {
+template <class P>
+struct ParamTraits;
+}  // namespace IPC
+
 namespace ipc_fuzzer {
 template <class T>
 struct FuzzTraits;