Record Startup.LoadTime.ProcessCreateToApplicationStart on Android

This metric was not previously recorded on Android because
startup_metric_utils::RecordStartupProcessCreationTime was never called.
We can use Process.getStartUptimeMillis() to get this value.

Bug: 1126301
Change-Id: Ic94be3635389c4a3c9b5e0f870b9d3290767a530
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2402209
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806384}

chrome/android/java/src/org/chromium/chrome/browser/metrics/UmaUtils.java

@@ -89,13 +89,18 @@ public class UmaUtils {
     }
 
     @CalledByNative
-    public static long getApplicationStartTime(boolean useProcessStartTime) {
-        if (useProcessStartTime && Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
-            return ApiHelperForN.getStartUptimeMillis();
-        }
+    public static long getApplicationStartTime() {
         return sApplicationStartTimeMs;
     }
 
+    @CalledByNative
+    public static long getProcessStartTime() {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {
+            return 0;
+        }
+        return ApiHelperForN.getStartUptimeMillis();
+    }
+
     public static long getForegroundStartTicks() {
         assert sForegroundStartTimeMs != 0;
         return sForegroundStartTimeMs;

chrome/app/android/chrome_main_delegate_android.cc

@@ -92,9 +92,19 @@ int ChromeMainDelegateAndroid::RunProcess(
   // Also only record the start time the first time round, since this is the
   // start time of the application, and will be same for all requests.
   if (!browser_runner_) {
-    startup_metric_utils::RecordApplicationStartTime(
-        chrome::android::GetApplicationStartTime(
-            base::FeatureList::IsEnabled(kUseProcessStartTimeForMetrics)));
+    base::TimeTicks process_start_time = chrome::android::GetProcessStartTime();
+    base::TimeTicks application_start_time =
+        chrome::android::GetApplicationStartTime();
+    if (!process_start_time.is_null()) {
+      startup_metric_utils::RecordStartupProcessCreationTime(
+          process_start_time);
+      // TODO(crbug.com/1127482): Perf bots should add support for measuring
+      // Startup.LoadTime.ProcessCreateToApplicationStart, then the
+      // kUseProcessStartTimeForMetrics feature can be removed.
+      if (base::FeatureList::IsEnabled(kUseProcessStartTimeForMetrics))
+        application_start_time = process_start_time;
+    }
+    startup_metric_utils::RecordApplicationStartTime(application_start_time);
     browser_runner_ = content::BrowserMainRunner::Create();
   }
 

chrome/app/chrome_main_delegate.cc

@@ -493,7 +493,8 @@ void RecordMainStartupMetrics(base::TimeTicks application_start_time) {
 
 #if defined(OS_MAC) || defined(OS_WIN) || defined(OS_LINUX) || \
     defined(OS_CHROMEOS)
-  // Record the startup process creation time on supported platforms.
+  // Record the startup process creation time on supported platforms. On Android
+  // this is recorded in ChromeMainDelegateAndroid.
   startup_metric_utils::RecordStartupProcessCreationTime(
       base::Process::Current().CreationTime());
 #endif

chrome/browser/android/metrics/uma_utils.cc

@@ -18,10 +18,16 @@ class PrefService;
 namespace chrome {
 namespace android {
 
-base::TimeTicks GetApplicationStartTime(bool use_process_start_time) {
+base::TimeTicks GetApplicationStartTime() {
   JNIEnv* env = base::android::AttachCurrentThread();
   return base::TimeTicks::FromUptimeMillis(
-      Java_UmaUtils_getApplicationStartTime(env, use_process_start_time));
+      Java_UmaUtils_getApplicationStartTime(env));
+}
+
+base::TimeTicks GetProcessStartTime() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  return base::TimeTicks::FromUptimeMillis(
+      Java_UmaUtils_getProcessStartTime(env));
 }
 
 static jboolean JNI_UmaUtils_IsClientInMetricsReportingSample(JNIEnv* env) {

chrome/browser/android/metrics/uma_utils.h

@@ -12,7 +12,8 @@
 namespace chrome {
 namespace android {
 
-base::TimeTicks GetApplicationStartTime(bool use_process_start_time);
+base::TimeTicks GetApplicationStartTime();
+base::TimeTicks GetProcessStartTime();
 
 // Sets whether UMA reporting is enabled. This will call to Java to update
 // the shared preference that is the source of truth for UMA reporting.

components/startup_metric_utils/browser/startup_metric_utils.cc

@@ -376,8 +376,12 @@ void SetBackgroundModeEnabled() {
 }
 
 void RecordStartupProcessCreationTime(base::Time time) {
+  RecordStartupProcessCreationTime(StartupTimeToTimeTicks(time));
+}
+
+void RecordStartupProcessCreationTime(base::TimeTicks ticks) {
   DCHECK(g_process_creation_ticks.is_null());
-  g_process_creation_ticks = StartupTimeToTimeTicks(time);
+  g_process_creation_ticks = ticks;
   DCHECK(!g_process_creation_ticks.is_null());
 }
 

components/startup_metric_utils/browser/startup_metric_utils.h

@@ -34,6 +34,7 @@ void SetBackgroundModeEnabled();
 
 // Call this with the creation time of the startup (initial/main) process.
 void RecordStartupProcessCreationTime(base::Time time);
+void RecordStartupProcessCreationTime(base::TimeTicks ticks);
 
 // Call this with a time recorded as early as possible in the startup process.
 // On Android, the application start is the time at which the Java code starts.