GN build improvements.

net/BUILD.gn

Index: net/BUILD.gn
diff --git a/net/BUILD.gn b/net/BUILD.gn
index 41508a4082ceaf85d74742261593a486acfc98cf..6ee299aa66339e2ca55defd34f4b80207fedcc0e 100644
--- a/net/BUILD.gn
+++ b/net/BUILD.gn
@@ -160,29 +160,14 @@ component("net") {
 
   if (use_openssl) {
     sources -= [
-      "base/crypto_module_nss.cc",
-      "base/keygen_handler_nss.cc",
       "base/nss_memio.c",
       "base/nss_memio.h",
-      "cert/cert_database_nss.cc",
-      "cert/cert_verify_proc_nss.cc",
-      "cert/cert_verify_proc_nss.h",
       "cert/ct_log_verifier_nss.cc",
       "cert/ct_objects_extractor_nss.cc",
       "cert/jwk_serializer_nss.cc",
-      "cert/nss_cert_database.cc",
-      "cert/nss_cert_database.h",
-      "cert/nss_cert_database_chromeos.cc",
-      "cert/nss_cert_database_chromeos.h",
-      "cert/nss_profile_filter_chromeos.cc",
-      "cert/nss_profile_filter_chromeos.h",
       "cert/scoped_nss_types.h",
-      "cert/test_root_certs_nss.cc",
-      "cert/x509_certificate_nss.cc",
       "cert/x509_util_nss.cc",
       "cert/x509_util_nss.h",
-      "ocsp/nss_ocsp.cc",
-      "ocsp/nss_ocsp.h",
       "quic/crypto/aead_base_decrypter_nss.cc",
       "quic/crypto/aead_base_encrypter_nss.cc",
       "quic/crypto/aes_128_gcm_12_decrypter_nss.cc",
@@ -197,13 +182,42 @@ component("net") {
       "socket/ssl_client_socket_nss.h",
       "socket/ssl_server_socket_nss.cc",
       "socket/ssl_server_socket_nss.h",
-      "third_party/mozilla_security_manager/nsKeygenHandler.cpp",
-      "third_party/mozilla_security_manager/nsKeygenHandler.h",
-      "third_party/mozilla_security_manager/nsNSSCertificateDB.cpp",
-      "third_party/mozilla_security_manager/nsNSSCertificateDB.h",
-      "third_party/mozilla_security_manager/nsPKCS12Blob.cpp",
-      "third_party/mozilla_security_manager/nsPKCS12Blob.h",
     ]
+    if (is_chromeos) {
+      sources -= [
+        "cert/nss_cert_database_chromeos.cc",
+        "cert/nss_cert_database_chromeos.h",
+        "cert/nss_profile_filter_chromeos.cc",
+        "cert/nss_profile_filter_chromeos.h",
+      ]
+    }
+    if (is_linux) {
+      # These are always removed for non-Linux cases below.
+      sources -= [
+        "base/crypto_module_nss.cc",
+        "base/keygen_handler_nss.cc",
+        "cert/cert_database_nss.cc",
+        "cert/nss_cert_database.cc",
+        "cert/nss_cert_database.h",
+        "cert/x509_certificate_nss.cc",
+        "third_party/mozilla_security_manager/nsKeygenHandler.cpp",
+        "third_party/mozilla_security_manager/nsKeygenHandler.h",
+        "third_party/mozilla_security_manager/nsNSSCertificateDB.cpp",
+        "third_party/mozilla_security_manager/nsNSSCertificateDB.h",
+        "third_party/mozilla_security_manager/nsPKCS12Blob.cpp",
+        "third_party/mozilla_security_manager/nsPKCS12Blob.h",
+      ]
+    }
+    if (is_ios) {
+      # Always removed for !ios below.
+      sources -= [
+        "cert/cert_verify_proc_nss.cc",
+        "cert/cert_verify_proc_nss.h",
+        "cert/test_root_certs_nss.cc",
+        "ocsp/nss_ocsp.cc",
+        "ocsp/nss_ocsp.h",
+      ]
+    }
   } else {
     sources -= [
       "base/crypto_module_openssl.cc",
@@ -433,12 +447,6 @@ component("net") {
 
   if (is_android) {
     if (!is_android_webview_build) {
-      sources -= [
-        "base/openssl_private_key_store_memory.cc",
-        "cert/cert_database_openssl.cc",
-        "cert/cert_verify_proc_openssl.cc",
-        "cert/test_root_certs_openssl.cc",
-      ]
       deps += [ ":net_jni_headers" ]
 
       # The net/android/keystore_openssl.cc source file needs to access an