metrics: Report special OS name for Lacros browser binary

The Lacros browser runs on Chrome OS, but reports a special OS name to
differentiate itself from the built-in ash browser + window manager
binary.

See bug for link to discussion thread.

Bug: 1096268
Test: added to components_unittests
Change-Id: I37fd53c956b69c991732f58c69a20331addfcbc6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2284228Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#785955}

components/metrics/BUILD.gn

@@ -143,6 +143,7 @@ jumbo_static_library("metrics") {
     "//base",
     "//base:base_static",
     "//build:branding_buildflags",
+    "//build:lacros_buildflags",
     "//components/prefs",
     "//components/variations",
     "//components/version_info:version_info",
@@ -465,6 +466,7 @@ source_set("unit_tests") {
     ":test_support",
     ":ui",
     "//base/test:test_support",
+    "//build:lacros_buildflags",
     "//components/component_updater:test_support",
     "//components/encrypted_messages:encrypted_message_proto",
     "//components/prefs:test_support",

components/metrics/metrics_log.cc

@@ -24,6 +24,7 @@
 #include "base/system/sys_info.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
+#include "build/lacros_buildflags.h"
 #include "components/metrics/delegating_provider.h"
 #include "components/metrics/environment_recorder.h"
 #include "components/metrics/histogram_encoder.h"
@@ -208,7 +209,13 @@ void MetricsLog::RecordCoreSystemProfile(
 #endif
 
   metrics::SystemProfileProto::OS* os = system_profile->mutable_os();
+#if BUILDFLAG(IS_LACROS)
+  // The Lacros browser runs on Chrome OS, but reports a special OS name to
+  // differentiate itself from the built-in ash browser + window manager binary.
+  os->set_name("Lacros");
+#else
   os->set_name(base::SysInfo::OperatingSystemName());
+#endif
   os->set_version(base::SysInfo::OperatingSystemVersion());
 
 // On ChromeOS, KernelVersion refers to the Linux kernel version and

components/metrics/metrics_log_unittest.cc

@@ -19,6 +19,7 @@
 #include "base/system/sys_info.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
+#include "build/lacros_buildflags.h"
 #include "components/metrics/cpu_metrics_provider.h"
 #include "components/metrics/delegating_provider.h"
 #include "components/metrics/environment_recorder.h"
@@ -167,7 +168,11 @@ TEST_F(MetricsLogTest, BasicRecord) {
   hardware->set_dll_base(reinterpret_cast<uint64_t>(CURRENT_MODULE()));
 #endif
 
+#if BUILDFLAG(IS_LACROS)
+  system_profile->mutable_os()->set_name("Lacros");
+#else
   system_profile->mutable_os()->set_name(base::SysInfo::OperatingSystemName());
+#endif
   system_profile->mutable_os()->set_version(
       base::SysInfo::OperatingSystemVersion());
 #if defined(OS_CHROMEOS)