Use CLOCK_BOOTTIME for default sensor implementation

The sensor implementation used to generate periodic signals according to
CLOCK_REALTIME. The clock can be adjusted by user or synchronization
service and results in wrong period. This commit changes it to
CLOCK_BOOTTIME which is monotonic.

Test: atest VtsHalSensorsV2_0TargetTest
Test: atest VtsHalSensorsV2_1TargetTest
Test: atest CtsSensorTestCases
Bug: 194030777
Change-Id: Iac39c93d6d2518b1abe8fc07fd695b9bb2cf30a5
diff --git a/sensors/common/default/2.X/Sensor.cpp b/sensors/common/default/2.X/Sensor.cpp
index 1a7c628..23c9803 100644
--- a/sensors/common/default/2.X/Sensor.cpp
+++ b/sensors/common/default/2.X/Sensor.cpp
@@ -114,7 +114,7 @@
             });
         } else {
             timespec curTime;
-            clock_gettime(CLOCK_REALTIME, &curTime);
+            clock_gettime(CLOCK_BOOTTIME, &curTime);
             int64_t now = (curTime.tv_sec * kNanosecondsInSeconds) + curTime.tv_nsec;
             int64_t nextSampleTime = mLastSampleTimeNs + mSamplingPeriodNs;
 
diff --git a/sensors/common/default/2.X/multihal/tests/fake_subhal/Sensor.cpp b/sensors/common/default/2.X/multihal/tests/fake_subhal/Sensor.cpp
index 69debb6..f5745c5 100644
--- a/sensors/common/default/2.X/multihal/tests/fake_subhal/Sensor.cpp
+++ b/sensors/common/default/2.X/multihal/tests/fake_subhal/Sensor.cpp
@@ -125,7 +125,7 @@
             });
         } else {
             timespec curTime;
-            clock_gettime(CLOCK_REALTIME, &curTime);
+            clock_gettime(CLOCK_BOOTTIME, &curTime);
             int64_t now = (curTime.tv_sec * kNanosecondsInSeconds) + curTime.tv_nsec;
             int64_t nextSampleTime = mLastSampleTimeNs + mSamplingPeriodNs;