Replace future elapsedRealtime with system clock

Bug: 314328533
Test: on cuttlefish
Change-Id: Ide876ff5bed855972a5c6e2f853c173b5e652535
diff --git a/AconfigFlags.bp b/AconfigFlags.bp
index c477a75..9e30843 100644
--- a/AconfigFlags.bp
+++ b/AconfigFlags.bp
@@ -180,6 +180,12 @@
     ],
 }
 
+cc_aconfig_library {
+    name: "android_location_flags_c_lib",
+    vendor_available: true,
+    aconfig_declarations: "android.location.flags-aconfig",
+}
+
 java_aconfig_library {
     name: "android.location.flags-aconfig-java",
     aconfig_declarations: "android.location.flags-aconfig",
@@ -256,7 +262,6 @@
     defaults: ["framework-minus-apex-aconfig-java-defaults"],
 }
 
-
 // OS
 aconfig_declarations {
     name: "android.os.flags-aconfig",
diff --git a/location/java/android/location/flags/gnss.aconfig b/location/java/android/location/flags/gnss.aconfig
index 794a555..5f1279e 100644
--- a/location/java/android/location/flags/gnss.aconfig
+++ b/location/java/android/location/flags/gnss.aconfig
@@ -41,3 +41,10 @@
     description: "Flag for GNSS configuration from resource"
     bug: "317734846"
 }
+
+flag {
+    name: "replace_future_elapsed_realtime_jni"
+    namespace: "location"
+    description: "Flag for replacing future elapsedRealtime in JNI"
+    bug: "314328533"
+}
diff --git a/services/core/jni/gnss/Android.bp b/services/core/jni/gnss/Android.bp
index f3ba484f62..e72259f 100644
--- a/services/core/jni/gnss/Android.bp
+++ b/services/core/jni/gnss/Android.bp
@@ -68,5 +68,6 @@
         "android.hardware.gnss@2.1",
         "android.hardware.gnss.measurement_corrections@1.0",
         "android.hardware.gnss.visibility_control@1.0",
+        "android_location_flags_c_lib",
     ],
 }
diff --git a/services/core/jni/gnss/Utils.cpp b/services/core/jni/gnss/Utils.cpp
index 571534f..274e3b7 100644
--- a/services/core/jni/gnss/Utils.cpp
+++ b/services/core/jni/gnss/Utils.cpp
@@ -20,6 +20,7 @@
 
 #include <android/hardware/gnss/1.0/IGnss.h>
 #include <android/hardware/gnss/2.0/IGnss.h>
+#include <android_location_flags.h>
 #include <utils/SystemClock.h>
 /*
  * Save a pointer to JavaVm to attach/detach threads executing
@@ -27,6 +28,8 @@
  */
 JavaVM* android::ScopedJniThreadAttach::sJvm;
 
+namespace location_flags = android::location::flags;
+
 namespace android {
 
 namespace {
@@ -194,7 +197,12 @@
 
     flags = static_cast<uint32_t>(location.elapsedRealtime.flags);
     if (flags & android::hardware::gnss::ElapsedRealtime::HAS_TIMESTAMP_NS) {
-        SET(ElapsedRealtimeNanos, location.elapsedRealtime.timestampNs);
+        if (location_flags::replace_future_elapsed_realtime_jni() &&
+            location.elapsedRealtime.timestampNs > android::elapsedRealtimeNano()) {
+            SET(ElapsedRealtimeNanos, android::elapsedRealtimeNano());
+        } else {
+            SET(ElapsedRealtimeNanos, location.elapsedRealtime.timestampNs);
+        }
     } else {
         SET(ElapsedRealtimeNanos, android::elapsedRealtimeNano());
     }