Added a new Stopwatch class to easily log timings.

src/org/thoughtcrime/securesms/util/Stopwatch.java

@@ -0,0 +1,58 @@
+package org.thoughtcrime.securesms.util;
+
+import android.support.annotation.NonNull;
+
+import org.thoughtcrime.securesms.logging.Log;
+
+import java.util.LinkedList;
+import java.util.List;
+
+public class Stopwatch {
+
+  private final long        startTime;
+  private final String      title;
+  private final List<Split> splits;
+
+  public Stopwatch(@NonNull String title) {
+    this.startTime = System.currentTimeMillis();
+    this.title     = title;
+    this.splits    = new LinkedList<>();
+  }
+
+  public void split(@NonNull String label) {
+    splits.add(new Split(System.currentTimeMillis(), label));
+  }
+
+  public void stop(@NonNull String tag) {
+    StringBuilder out = new StringBuilder();
+    out.append("[").append(title).append("] ");
+
+    if (splits.size() > 0) {
+      out.append(splits.get(0).label).append(": ");
+      out.append(splits.get(0).time - startTime);
+      out.append("  ");
+    }
+
+    if (splits.size() > 1) {
+      for (int i = 1; i < splits.size(); i++) {
+        out.append(splits.get(i).label).append(": ");
+        out.append(splits.get(i).time - splits.get(i - 1).time);
+        out.append("  ");
+      }
+
+      out.append("total: ").append(splits.get(splits.size() - 1).time - startTime);
+    }
+
+    Log.d(tag, out.toString());
+  }
+
+  private static class Split {
+    final long   time;
+    final String label;
+
+    Split(long time, String label) {
+      this.time  = time;
+      this.label = label;
+    }
+  }
+}