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.h b/services/camera/libcameraservice/device3/Camera3Device.h
index 4ffdc5f..f2394ad 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.h
+++ b/services/camera/libcameraservice/device3/Camera3Device.h
@@ -106,6 +106,9 @@
     status_t initialize(sp<CameraProviderManager> manager, const String8& monitorTags) override;
     status_t disconnect() override;
     status_t dump(int fd, const Vector<String16> &args) override;
+    status_t startWatchingTags(const String8 &tags) override;
+    status_t stopWatchingTags() override;
+    status_t dumpWatchedEventsToVector(std::vector<std::string> &out) override;
     const CameraMetadata& info() const override;
     const CameraMetadata& infoPhysical(const String8& physicalId) const override;