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/common/Camera2ClientBase.cpp b/services/camera/libcameraservice/common/Camera2ClientBase.cpp
index 1147e23..0283d01 100644
--- a/services/camera/libcameraservice/common/Camera2ClientBase.cpp
+++ b/services/camera/libcameraservice/common/Camera2ClientBase.cpp
@@ -155,6 +155,38 @@
 }
 
 template <typename TClientBase>
+status_t Camera2ClientBase<TClientBase>::startWatchingTags(const String8 &tags, int out) {
+  sp<CameraDeviceBase> device = mDevice;
+  if (!device) {
+    dprintf(out, "  Device is detached");
+    return OK;
+  }
+
+  return device->startWatchingTags(tags);
+}
+
+template <typename TClientBase>
+status_t Camera2ClientBase<TClientBase>::stopWatchingTags(int out) {
+  sp<CameraDeviceBase> device = mDevice;
+  if (!device) {
+    dprintf(out, "  Device is detached");
+    return OK;
+  }
+
+  return device->stopWatchingTags();
+}
+
+template <typename TClientBase>
+status_t Camera2ClientBase<TClientBase>::dumpWatchedEventsToVector(std::vector<std::string> &out) {
+    sp<CameraDeviceBase> device = mDevice;
+    if (!device) {
+        // Nothing to dump if the device is detached
+        return OK;
+    }
+    return device->dumpWatchedEventsToVector(out);
+}
+
+template <typename TClientBase>
 status_t Camera2ClientBase<TClientBase>::dumpDevice(
                                                 int fd,
                                                 const Vector<String16>& args) {