RESTRICT AUTOMERGE: Camera: fix use after free in sensor timestamp

The metadata object might be overriden later and has it memory
re-allocated; hence snaping the sensor timestamp value before
we call into any method that might change the metadata.

Test: build
Bug: 150944913
Merged-In: I0f944fc9133d3ab279859f20236d956d7ca338f8
Change-Id: I5b10b680e0cce96ca49e1772770adb4835545472

services/camera/libcameraservice/device3/Camera3Device.cpp

diff --git a/services/camera/libcameraservice/device3/Camera3Device.cpp b/services/camera/libcameraservice/device3/Camera3Device.cpp
index a8e80fa..e347127 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.cpp
+++ b/services/camera/libcameraservice/device3/Camera3Device.cpp
@@ -3521,6 +3521,8 @@
                 frameNumber);
         return;
     }
+    nsecs_t sensorTimestamp = timestamp.data.i64[0];
+
     for (auto& physicalMetadata : captureResult.mPhysicalMetadatas) {
         camera_metadata_entry timestamp =
                 physicalMetadata.mPhysicalCameraMetadata.find(ANDROID_SENSOR_TIMESTAMP);
@@ -3575,7 +3577,7 @@
                 CameraMetadata(m.mPhysicalCameraMetadata));
     }
     mTagMonitor.monitorMetadata(TagMonitor::RESULT,
-            frameNumber, timestamp.data.i64[0], captureResult.mMetadata,
+            frameNumber, sensorTimestamp, captureResult.mMetadata,
             monitoredPhysicalMetadata);
 
     insertResultLocked(&captureResult, frameNumber);