Provide hardware model name for ClonedInstallDetector

When running on a non-windows platform, MachineIdProvider will provide the hardware model name.

Bug: 981408
Change-Id: I1edae511b1e79cb2360630c1253c4e7209aeec3b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2088531
Commit-Queue: Adam Trudeau-Arcaro <adamta@google.com>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747763}

components/metrics/BUILD.gn

@@ -74,7 +74,7 @@ jumbo_static_library("metrics") {
     "log_decoder.h",
     "log_store.h",
     "machine_id_provider.h",
-    "machine_id_provider_stub.cc",
+    "machine_id_provider_nonwin.cc",
     "machine_id_provider_win.cc",
     "metrics_log.cc",
     "metrics_log.h",
@@ -165,7 +165,7 @@ jumbo_static_library("metrics") {
   }
 
   if (is_win) {
-    sources -= [ "machine_id_provider_stub.cc" ]
+    sources -= [ "machine_id_provider_nonwin.cc" ]
     deps += [ "//components/browser_watcher:stability_client" ]
     libs = [ "wevtapi.lib" ]
   }
@@ -404,7 +404,7 @@ source_set("unit_tests") {
     "field_trials_provider_unittest.cc",
     "file_metrics_provider_unittest.cc",
     "histogram_encoder_unittest.cc",
-    "machine_id_provider_win_unittest.cc",
+    "machine_id_provider_nonwin_unittest.cc",
     "metrics_log_manager_unittest.cc",
     "metrics_log_store_unittest.cc",
     "metrics_log_unittest.cc",
@@ -450,6 +450,11 @@ source_set("unit_tests") {
     "//ui/gfx/geometry",
   ]
 
+  if (is_win) {
+    sources -= [ "machine_id_provider_nonwin_unittest.cc" ]
+    sources += [ "machine_id_provider_win_unittest.cc" ]
+  }
+
   if (is_linux) {
     sources += [ "serialization/serialization_utils_unittest.cc" ]
     deps += [ ":serialization" ]

components/metrics/cloned_install_detector.cc

@@ -55,6 +55,9 @@ ClonedInstallDetector::~ClonedInstallDetector() {
 }
 
 void ClonedInstallDetector::CheckForClonedInstall(PrefService* local_state) {
+  if (!MachineIdProvider::HasId())
+    return;
+
   base::ThreadPool::PostTaskAndReplyWithResult(
       FROM_HERE,
       {base::MayBlock(), base::TaskPriority::BEST_EFFORT,

components/metrics/machine_id_provider.h

@@ -23,8 +23,9 @@ class MachineIdProvider {
   static bool HasId();
 
   // Get a string containing machine characteristics, to be used as a machine
-  // id. The implementation is platform specific, with a default implementation
-  // returning an empty string.
+  // id. The implementation is split into Windows and non-Windows. The former
+  // returns the drive serial number and the latter returns the hardware
+  // model name. Should not be called if HasId() returns false.
   // The return value should not be stored to disk or transmitted.
   static std::string GetMachineId();
 

components/metrics/machine_id_provider_stub.cc → components/metrics/machine_id_provider_nonwin.cc

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// Copyright 2020 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 "components/metrics/machine_id_provider.h"
 
-#include "base/logging.h"
+#include <stdint.h>
+
+#include "base/system/sys_info.h"
 
 namespace metrics {
 
-// static
+// Checks if hardware model name is available.
 bool MachineIdProvider::HasId() {
-  return false;
+  return !base::SysInfo::HardwareModelName().empty();
 }
 
-// static
+// On non-windows, the machine id is based on the hardware model name.
+// This will suffice as users are unlikely to change to the same machine model.
 std::string MachineIdProvider::GetMachineId() {
-  NOTREACHED();
-  return std::string();
-}
+  // Gets hardware model name. (e.g. 'Macbook Pro 16,1', 'iPhone 9,3')
+  std::string hardware_model_name = base::SysInfo::HardwareModelName();
 
+  // This function should not be called if hardware model name is unavailable.
+  DCHECK(!hardware_model_name.empty());
+
+  return hardware_model_name;
+}
 }  //  namespace metrics

components/metrics/machine_id_provider_nonwin_unittest.cc

+// Copyright 2020 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 "components/metrics/machine_id_provider.h"
+
+#include "base/system/sys_info.h"
+#include "build/build_config.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace metrics {
+
+TEST(MachineIdProviderNonWinTest, GetId) {
+  const bool has_machine_name = !base::SysInfo::HardwareModelName().empty();
+
+#if defined(OS_ANDROID) || defined(OS_MACOSX) || defined(OS_IOS)
+  DCHECK(has_machine_name);
+#endif
+
+  // Should only return a machine ID if the hardware model name is available.
+  if (has_machine_name) {
+    const std::string id1 = MachineIdProvider::GetMachineId();
+    EXPECT_TRUE(MachineIdProvider::HasId());
+    EXPECT_NE(std::string(), id1);
+
+    const std::string id2 = MachineIdProvider::GetMachineId();
+    EXPECT_EQ(id1, id2);
+  } else {
+    EXPECT_FALSE(MachineIdProvider::HasId());
+  }
+}
+
+}  // namespace metrics

components/metrics/machine_id_provider_win_unittest.cc

@@ -8,7 +8,7 @@
 
 namespace metrics {
 
-TEST(MachineIdProviderTest, GetId) {
+TEST(MachineIdProviderWinTest, GetId) {
   EXPECT_TRUE(MachineIdProvider::HasId());
 
   const std::string id1 = MachineIdProvider::GetMachineId();

components/metrics/metrics_state_manager.cc

@@ -22,7 +22,6 @@
 #include "components/metrics/cloned_install_detector.h"
 #include "components/metrics/enabled_state_provider.h"
 #include "components/metrics/entropy_state.h"
-#include "components/metrics/machine_id_provider.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/metrics_pref_names.h"
 #include "components/metrics/metrics_provider.h"
@@ -292,9 +291,6 @@ void MetricsStateManager::ForceClientIdCreation() {
 }
 
 void MetricsStateManager::CheckForClonedInstall() {
-  if (!MachineIdProvider::HasId())
-    return;
-
   cloned_install_detector_.CheckForClonedInstall(local_state_);
 }