dbus-vis: Fix counts for overlapped entries

For dbus method calls that overlap in time, the Render() routine used to
only report counts from the last row. This has been corrected such that
the sum of the counts from all rows belonging to the same same are added
together.

Signed-off-by: Sui Chen <suichen@google.com>
Change-Id: I6c87a0f52c6ab766ecd452305f989ad819b886a5
diff --git a/dbus-vis/dbus_timeline_vis.js b/dbus-vis/dbus_timeline_vis.js
index 8d4f583..9c2dd2a 100644
--- a/dbus-vis/dbus_timeline_vis.js
+++ b/dbus-vis/dbus_timeline_vis.js
@@ -218,7 +218,7 @@
     let rise_fall_edges = [];
     the_header.intervals_idxes.forEach((i) => {
       intervals[i].forEach((t0t1) => {
-        if (t0t1[0] <= t0t1[1]) {  // For errored-out method calls, the end time will be set to a value smaller than the start tiem
+        if (t0t1[0] <= t0t1[1]) {  // For errored-out method calls, the end time will be set to a value smaller than the start time
           rise_fall_edges.push([t0t1[0], 0]);  // 0 is a rising edge
           rise_fall_edges.push([t0t1[1], 1]);  // 1 is a falling edge
         }