Add a log viewer to Spinner.

This is more of a proof-of-concept/demo for using a websocket with
Spinner. Gives an example of how we could push live updates to the
webapp.

Also, the logger is actually nice. Guaranteed to never get cluttered
with system logs. Looks basically identical to our other log viewers.
Filtering is basic but fast. And we could build much better tooling on
top of this.

spinner/app/src/main/java/org/signal/spinnertest/MainActivity.kt

@@ -3,10 +3,16 @@ package org.signal.spinnertest
 import android.database.sqlite.SQLiteDatabase
 import android.os.Build
 import android.os.Bundle
+import android.widget.Button
 import androidx.appcompat.app.AppCompatActivity
 import androidx.core.content.contentValuesOf
+import org.signal.core.util.ThreadUtil
+import org.signal.core.util.logging.AndroidLogger
+import org.signal.core.util.logging.Log
 import org.signal.spinner.Spinner
+import org.signal.spinner.SpinnerLogger
 import java.util.UUID
+import kotlin.random.Random
 
 class MainActivity : AppCompatActivity() {
   override fun onCreate(savedInstanceState: Bundle?) {
@@ -26,6 +32,25 @@ class MainActivity : AppCompatActivity() {
       mapOf("main" to Spinner.DatabaseConfig(db = { db })),
       emptyMap()
     )
+
+    Log.initialize(AndroidLogger(), SpinnerLogger())
+
+    object : Thread() {
+      override fun run() {
+        while (true) {
+          when (Random.nextInt(0, 5)) {
+            0 -> Log.v("MyTag", "Message: ${System.currentTimeMillis()}")
+            1 -> Log.d("MyTag", "Message: ${System.currentTimeMillis()}")
+            2 -> Log.i("MyTag", "Message: ${System.currentTimeMillis()}")
+            3 -> Log.w("MyTag", "Message: ${System.currentTimeMillis()}")
+            4 -> Log.e("MyTag", "Message: ${System.currentTimeMillis()}")
+          }
+          ThreadUtil.sleep(Random.nextLong(0, 200))
+        }
+      }
+    }.start()
+
+    findViewById<Button>(R.id.log_throwable_button).setOnClickListener { Log.e("MyTag", "Message: ${System.currentTimeMillis()}", Throwable()) }
   }
 
   private fun insertMockData(db: SQLiteDatabase) {

spinner/app/src/main/res/layout/activity_main.xml

@@ -27,4 +27,10 @@
         android:layout_height="match_parent"
         android:text="Then go to localhost:5000 in your browser." />
 
+    <Button
+        android:id="@+id/log_throwable_button"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="Log Throwable" />
+
 </LinearLayout>