[remoting] Add GN switch for WebRTC debug logs.

In the host process, the WebRTC "VERBOSE1" logs are extremely spammy,
and they cannot be filtered separately from "INFO" messages using --v or
--vmodule switches (the third_party/webrtc_overrides implementation sets
them to the same log verbosity level).

To make these logs optional and easy to enable, this CL provides a
GN argument "remoting_webrtc_verbose_logging" with a default value of
false. Because of the huge amount of logs generated, this is set to
false even for Debug builds.

This CL also replaces AppendSwitch(..) with the corrected call to
AppendSwitchASCII(). The former, when passed "key=value", would set a
command-line switch literally named "key=value", whose value was an
empty string. So the WebRTC debug logs were never enabled even in Debug
builds.

Change-Id: I2a3b5c0130f4bb004b1ebf7433fc5097513b6559
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2725024
Commit-Queue: Lambros Lambrou <lambroslambrou@chromium.org>
Auto-Submit: Lambros Lambrou <lambroslambrou@chromium.org>
Reviewed-by: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#858408}

remoting/build/config/remoting_logging.gni

@@ -0,0 +1,14 @@
+# Copyright 2021 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+declare_args() {
+  # Enabling this will cause WebRTC's LS_INFO and LS_VERBOSE (level 1)
+  # messages to appear in the debug log output. Note that WebRTC's
+  # "VERBOSE1" messages are very spammy and it is impossible to
+  # separately filter LS_INFO and LS_VERBOSE messages (see
+  # third_party/webrtc_overrides/rtc_base/). So a separate GN option is
+  # provided here, to allow this logging to be quickly enabled for Debug
+  # or Release builds.
+  remoting_webrtc_verbose_logging = false
+}

remoting/host/BUILD.gn

@@ -6,6 +6,7 @@ import("//build/config/chromeos/ui_mode.gni")
 import("//build/config/python.gni")
 import("//build/util/process_version.gni")
 import("//remoting/build/config/remoting_build.gni")
+import("//remoting/build/config/remoting_logging.gni")
 
 group("all_tests") {
   testonly = true
@@ -46,19 +47,10 @@ source_set("host") {
   deps = [ "//remoting/host/file_transfer" ]
 }
 
-source_set("base") {
+source_set("logging") {
   sources = [
-    "host_exit_codes.cc",
-    "host_exit_codes.h",
+    "logging.cc",
     "logging.h",
-    "switches.cc",
-    "switches.h",
-    "username.cc",
-    "username.h",
-  ]
-  deps = [
-    "//base",
-    "//remoting/base",
   ]
 
   if (is_linux || is_chromeos) {
@@ -72,6 +64,27 @@ source_set("base") {
   if (is_win) {
     sources += [ "logging_win.cc" ]
   }
+
+  if (remoting_webrtc_verbose_logging) {
+    defines = [ "WEBRTC_VERBOSE_LOGGING" ]
+  }
+}
+
+source_set("base") {
+  sources = [
+    "host_exit_codes.cc",
+    "host_exit_codes.h",
+    "switches.cc",
+    "switches.h",
+    "username.cc",
+    "username.h",
+  ]
+  deps = [
+    ":logging",
+    "//base",
+    "//remoting/base",
+  ]
+  public_deps = [ ":logging" ]
 }
 
 # Split up from common to avoid circular dependency.

remoting/host/host_main.cc

@@ -167,15 +167,6 @@ int HostMain(int argc, char** argv) {
 
   base::CommandLine::Init(argc, argv);
 
-#if !defined(NDEBUG)
-  // Always enable Webrtc logging for debug builds.
-  // Without this switch, Webrtc errors will still be logged but
-  // RTC_LOG(LS_INFO) lines will not.
-  // See https://webrtc.org/native-code/logging
-  auto* cl = base::CommandLine::ForCurrentProcess();
-  cl->AppendSwitch("vmodule=*/webrtc/*=1");
-#endif
-
   // Parse the command line.
   const base::CommandLine* command_line =
       base::CommandLine::ForCurrentProcess();

remoting/host/logging.cc

@@ -0,0 +1,18 @@
+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/host/logging.h"
+
+#include "base/command_line.h"
+
+namespace remoting {
+
+void InitHostLoggingCommon() {
+#ifdef WEBRTC_VERBOSE_LOGGING
+  base::CommandLine::ForCurrentProcess()->AppendSwitchASCII("vmodule",
+                                                            "*/webrtc/*=1");
+#endif
+}
+
+}  // namespace remoting

remoting/host/logging.h

@@ -24,7 +24,10 @@ constexpr GUID kRemotingHostLogProviderGuid = {
 #endif
 
 // Initializes host logging.
-extern void InitHostLogging();
+void InitHostLogging();
+
+// Common initialization for all platforms, called by InitHostLogging().
+void InitHostLoggingCommon();
 
 }  // namespace remoting
 

remoting/host/logging_linux.cc

@@ -9,6 +9,8 @@
 namespace remoting {
 
 void InitHostLogging() {
+  InitHostLoggingCommon();
+
   // Write logs to the system debug log.
   logging::LoggingSettings settings;
   settings.logging_dest =

remoting/host/logging_mac.cc

@@ -88,6 +88,8 @@ bool LogMessageToAsl(
 }  // namespace
 
 void InitHostLogging() {
+  InitHostLoggingCommon();
+
   // Write logs to the system debug log.
   logging::LoggingSettings settings;
   settings.logging_dest =

remoting/host/logging_win.cc

@@ -12,6 +12,8 @@
 namespace remoting {
 
 void InitHostLogging() {
+  InitHostLoggingCommon();
+
   // Write logs to the system debug log.
   logging::LoggingSettings settings;
   settings.logging_dest =