Add 'watch' command to CameraService

Currently there is no way to monitor tags and dump per frame data from
Camera devices without calling dumpsys, which in turn dumps a lot of
unnecessary information.

This CL adds a 'watch' command to CameraService which can be called
through `cmd`. 'watch' provides a path to manage tag monitoring without
dumpsys. 'watch' currently has four functions:
1. start <taglist>: starts mornitoring the provided tags in attached
                    devices.
2. stop: stop monitoring all tags
3. live: prints monitored information to the terminal live
4. dump: dumps any collected camera traces

This CL adds a function to camera device each for the three tag
monitoring function listed above.

Test: n/a
Bug: 199746421
Change-Id: Ia5ce13f6e50c82085afcc676309cdbffef915a41
diff --git a/services/camera/libcameraservice/device3/Camera3Device.cpp b/services/camera/libcameraservice/device3/Camera3Device.cpp
index 67f99bf..8925b15 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.cpp
+++ b/services/camera/libcameraservice/device3/Camera3Device.cpp
@@ -848,6 +848,21 @@
     return OK;
 }
 
+status_t Camera3Device::startWatchingTags(const String8 &tags) {
+    mTagMonitor.parseTagsToMonitor(tags);
+    return OK;
+}
+
+status_t Camera3Device::stopWatchingTags() {
+    mTagMonitor.disableMonitoring();
+    return OK;
+}
+
+status_t Camera3Device::dumpWatchedEventsToVector(std::vector<std::string> &out) {
+    mTagMonitor.getLatestMonitoredTagEvents(out);
+    return OK;
+}
+
 const CameraMetadata& Camera3Device::infoPhysical(const String8& physicalId) const {
     ALOGVV("%s: E", __FUNCTION__);
     if (CC_UNLIKELY(mStatus == STATUS_UNINITIALIZED ||