Move enable_webrtc to a buildflag header.

chrome/browser/browser_process_impl.h

Index: chrome/browser/browser_process_impl.h
diff --git a/chrome/browser/browser_process_impl.h b/chrome/browser/browser_process_impl.h
index eb2a9cae4a8ccdfce2b956618a3d79d24df116e6..7033736182c47a5f4ddf65083893c8cc1cbf7753 100644
--- a/chrome/browser/browser_process_impl.h
+++ b/chrome/browser/browser_process_impl.h
@@ -26,6 +26,7 @@
 #include "chrome/common/features.h"
 #include "components/prefs/pref_change_registrar.h"
 #include "extensions/features/features.h"
+#include "media/media_features.h"
 #include "printing/features/features.h"
 
 class ChromeChildProcessWatcher;
@@ -147,7 +148,7 @@ class BrowserProcessImpl : public BrowserProcess,
   supervised_user_whitelist_installer() override;
   MediaFileSystemRegistry* media_file_system_registry() override;
   bool created_local_state() const override;
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
   WebRtcLogUploader* webrtc_log_uploader() override;
 #endif
   network_time::NetworkTimeTracker* network_time_tracker() override;
@@ -327,7 +328,7 @@ class BrowserProcessImpl : public BrowserProcess,
   // the callstack which released the final module reference count.
   base::debug::StackTrace release_last_reference_callstack_;
 
-#if defined(ENABLE_WEBRTC)
+#if BUILDFLAG(ENABLE_WEBRTC)
   // Lazily initialized.
   std::unique_ptr<WebRtcLogUploader> webrtc_log_uploader_;
 #endif