Reland "[remoting] Add GN switch for WebRTC debug logs."

This is a reland of f790c4c

Original change's description:
> [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}

Change-Id: Id3f54cc9cb6a24bc2214e6d64e3ef485ac591516
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2726819
Auto-Submit: Lambros Lambrou <lambroslambrou@chromium.org>
Commit-Queue: Joe Downing <joedow@chromium.org>
Reviewed-by: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#858477}

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 +64,29 @@ source_set("base") {
   if (is_win) {
     sources += [ "logging_win.cc" ]
   }
+
+  if (remoting_webrtc_verbose_logging) {
+    defines = [ "WEBRTC_VERBOSE_LOGGING" ]
+  }
+
+  deps = [ "//base" ]
+}
+
+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 =