Reland: Add hpack utilities and perftests to net GN

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index f75ad065a236e17e29b862cadbb690d65c24379b..42dc584116663456fa212ae6c3b7d4d4ce4704db 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -726,6 +726,7 @@ config("default_warnings") {
   if (is_win) {
     cflags = [
       "/WX",  # Treat warnings as errors.
+
       # Warnings permanently disabled:
 
       # TODO(GYP) The GYP build doesn't have this globally enabled but disabled
@@ -780,6 +781,7 @@ config("default_warnings") {
       # have to turn off this warning (and be careful about how object
       # destruction happens in such cases).
       "/wd4611",
+
       # Warnings to evaluate and possibly fix/reenable later:
 
       "/wd4100",  # Unreferenced formal function parameter.
@@ -923,6 +925,8 @@ config("wexit_time_destructors") {
 #
 # Note that this can be applied regardless of platform and architecture to
 # clean up the call sites. This will only apply the flag when necessary.
+#
+# TODO(jschuh): crbug.com/167187 fix this and delete this config.
 config("no_size_t_to_int_warning") {
   if (is_win && current_cpu == "x64") {
     cflags = [ "/wd4267" ]