Replace remaining gflags usages with rtc_base/flags

webrtc/logging/BUILD.gn

Index: webrtc/logging/BUILD.gn
diff --git a/webrtc/logging/BUILD.gn b/webrtc/logging/BUILD.gn
index b8d17573c17cfcf1a16b8d1abb88342d64222397..8f1e493209961e7daf7df080ac40cc123c635dfb 100644
--- a/webrtc/logging/BUILD.gn
+++ b/webrtc/logging/BUILD.gn
@@ -142,7 +142,6 @@ if (rtc_enable_protobuf) {
         "../system_wrappers:field_trial_default",
         "../system_wrappers:metrics_default",
         "../test:rtp_test_utils",
-        "//third_party/gflags",
       ]
       if (!build_with_chromium && is_clang) {
         # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
@@ -165,7 +164,6 @@ if (rtc_enable_protobuf) {
         # TODO(kwiberg): Remove this dependency.
         "../api/audio_codecs:audio_codecs_api",
         "../modules/rtp_rtcp:rtp_rtcp",
-        "//third_party/gflags",
       ]
       if (!build_with_chromium && is_clang) {
         # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
@@ -184,7 +182,6 @@ if (rtc_enable_protobuf) {
         ":rtc_event_log_impl",
         ":rtc_event_log_proto",
         "../rtc_base:rtc_base_approved",
-        "//third_party/gflags",
       ]
       if (!build_with_chromium && is_clang) {
         # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).