[Payments] Currency formatter for order amounts.

components/payments/BUILD.gn

Index: components/payments/BUILD.gn
diff --git a/components/payments/BUILD.gn b/components/payments/BUILD.gn
index bbdd5f599ccf8dc6bcdda1eab48928cd0d8c74f8..1cd2dc32dcdc9fd49e9e0e86793ac8b1fb0f70f7 100644
--- a/components/payments/BUILD.gn
+++ b/components/payments/BUILD.gn
@@ -50,6 +50,8 @@ if (!is_ios) {
 
 static_library("payment_validation") {
   sources = [
+    "currency_formatter.cc",
+    "currency_formatter.h",
     "payment_details_validation.cc",
     "payment_details_validation.h",
     "payments_validators.cc",
@@ -62,16 +64,23 @@ static_library("payment_validation") {
     "//third_party/re2:re2",
     "//url:url",
   ]
+
+  public_deps = [
+    "//third_party/icu:icu",
+  ]
 }
 
-static_library("unit_tests") {
+source_set("unit_tests") {
   testonly = true
   sources = [
+    "currency_formatter_unittest.cc",
     "payments_validators_test.cc",
   ]
 
   deps = [
     ":payment_validation",
+    "//base",
     "//testing/gtest",
+    "//third_party/icu:icu",
   ]
 }