Prefix ENABLE_RTC_EVENT_LOG with WEBRTC_.

Since this macro can be considered public, it makes sense to prefix it
with WEBRTC_ (also to avoid potential conflicts with client code).

This CL also removes some definitions of this macro in order to define
it only where it is strictly needed (it is only used in a .cc file).

Bug: webrtc:11142
Change-Id: Idce7389301e71d8434e238b3cf4ceaa9cf97cd87
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/161008
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29957}
diff --git a/BUILD.gn b/BUILD.gn
index f81ad5f..337be46 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -476,7 +476,6 @@
     }
 
     if (rtc_enable_protobuf) {
-      defines += [ "ENABLE_RTC_EVENT_LOG" ]
       deps += [ "logging:rtc_event_log_proto" ]
     }
   }
diff --git a/api/rtc_event_log/BUILD.gn b/api/rtc_event_log/BUILD.gn
index ef7ea2c..e853058 100644
--- a/api/rtc_event_log/BUILD.gn
+++ b/api/rtc_event_log/BUILD.gn
@@ -41,7 +41,7 @@
   ]
 
   if (rtc_enable_protobuf) {
-    defines = [ "ENABLE_RTC_EVENT_LOG" ]
+    defines = [ "WEBRTC_ENABLE_RTC_EVENT_LOG" ]
     deps += [ "../../logging:rtc_event_log_impl" ]
   }
 }
diff --git a/api/rtc_event_log/rtc_event_log_factory.cc b/api/rtc_event_log/rtc_event_log_factory.cc
index f88997b..2013584 100644
--- a/api/rtc_event_log/rtc_event_log_factory.cc
+++ b/api/rtc_event_log/rtc_event_log_factory.cc
@@ -15,7 +15,7 @@
 
 #include "rtc_base/checks.h"
 
-#ifdef ENABLE_RTC_EVENT_LOG
+#ifdef WEBRTC_ENABLE_RTC_EVENT_LOG
 #include "logging/rtc_event_log/rtc_event_log_impl.h"
 #endif
 
@@ -28,7 +28,7 @@
 
 std::unique_ptr<RtcEventLog> RtcEventLogFactory::CreateRtcEventLog(
     RtcEventLog::EncodingType encoding_type) {
-#ifdef ENABLE_RTC_EVENT_LOG
+#ifdef WEBRTC_ENABLE_RTC_EVENT_LOG
   return std::make_unique<RtcEventLogImpl>(encoding_type, task_queue_factory_);
 #else
   return std::make_unique<RtcEventLogNull>();
diff --git a/logging/BUILD.gn b/logging/BUILD.gn
index 983b913..8046137 100644
--- a/logging/BUILD.gn
+++ b/logging/BUILD.gn
@@ -197,7 +197,6 @@
   ]
 
   if (rtc_enable_protobuf) {
-    defines += [ "ENABLE_RTC_EVENT_LOG" ]
     deps += [
       ":ice_log",
       ":rtc_event_audio",
@@ -340,7 +339,6 @@
     rtc_library("rtc_event_log_tests") {
       testonly = true
       assert(rtc_enable_protobuf)
-      defines = [ "ENABLE_RTC_EVENT_LOG" ]
       sources = [
         "rtc_event_log/encoder/blob_encoding_unittest.cc",
         "rtc_event_log/encoder/delta_encoding_unittest.cc",
diff --git a/rtc_tools/BUILD.gn b/rtc_tools/BUILD.gn
index fb9f885..de5b909 100644
--- a/rtc_tools/BUILD.gn
+++ b/rtc_tools/BUILD.gn
@@ -276,7 +276,6 @@
         "rtc_event_log_visualizer/plot_python.h",
         "rtc_event_log_visualizer/triage_notifications.h",
       ]
-      defines = [ "ENABLE_RTC_EVENT_LOG" ]
       deps = [
         ":chart_proto",
         "../api:function_view",
@@ -321,7 +320,6 @@
         "rtc_event_log_visualizer/main.cc",
       ]
 
-      defines = [ "ENABLE_RTC_EVENT_LOG" ]
       deps = [
         ":event_log_visualizer_utils",
         "../api/neteq:neteq_api",