Stop about:tracing from dropping child slices of didNotFinish slices.

chrome/browser/resources/tracing/timeline_model_test.html

Index: chrome/browser/resources/tracing/timeline_model_test.html
diff --git a/chrome/browser/resources/tracing/timeline_model_test.html b/chrome/browser/resources/tracing/timeline_model_test.html
index b6bb2c8b30151f7d6a0a60cb465ef930dab9ab01..f0a7a5aa22bc34dfe74d5513720240f503b09a36 100644
--- a/chrome/browser/resources/tracing/timeline_model_test.html
+++ b/chrome/browser/resources/tracing/timeline_model_test.html
@@ -99,6 +99,67 @@ function testAutoclosing() {
   assertEquals((2 - 1) / 1000, slice.duration);
 }
 
+function testAutoclosingLoneBegin() {
+  var events = [
+    // Slice that doesn't finish.
+    {name: 'a', args: {}, pid: 1, ts: 1, cat: 'foo', tid: 1, ph: 'B'}
+  ];
+  var m = new tracing.TimelineModel(events);
+  var p = m.processes[1];
+  var t = p.threads[1];
+  var subRow = t.subRows[0];
+  var slice = subRow[0];
+  assertEquals('a', slice.title);
+  assertTrue(slice.didNotFinish);
+  assertEquals(0, slice.start);
+  assertEquals(0, slice.duration);
+}
+
+function testAutoclosingWithSubTasks() {
+  var events = [
+    {name: 'a', args: {}, pid: 1, ts: 1, cat: 'foo', tid: 1, ph: 'B'},
+    {name: 'b1', args: {}, pid: 1, ts: 2, cat: 'foo', tid: 1, ph: 'B'},
+    {name: 'b1', args: {}, pid: 1, ts: 3, cat: 'foo', tid: 1, ph: 'E'},
+    {name: 'b2', args: {}, pid: 1, ts: 3, cat: 'foo', tid: 1, ph: 'B'}
+  ];
+  var m = new tracing.TimelineModel(events);
+  var p = m.processes[1];
+  var t = p.threads[1];
+  assertEquals(2, t.subRows.length);
+  assertEquals(1, t.subRows[0].length);
+  assertEquals(2, t.subRows[1].length);
+}
+
+function testAutoclosingWithEventsOutsideRange() {
+  var events = [
+    // Slice that begins before min and ends after max of the other threads.
+    {name: 'a', args: {}, pid: 1, ts: 0, cat: 'foo', tid: 1, ph: 'B'},
+    {name: 'a', args: {}, pid: 1, ts: 3, cat: 'foo', tid: 1, ph: 'B'},
+
+    // Slice that does finish to give an 'end time' to establish a basis
+    {name: 'b', args: {}, pid: 1, ts: 1, cat: 'foo', tid: 2, ph: 'B'},
+    {name: 'b', args: {}, pid: 1, ts: 2, cat: 'foo', tid: 2, ph: 'E'}
+  ];
+  var m = new tracing.TimelineModel(events);
+  var p = m.processes[1];
+  var t = p.threads[1];
+  var subRow = t.subRows[0];
+  assertEquals('a', subRow[0].title);
+  assertEquals(0, subRow[0].start);
+  assertEquals(0.003, subRow[0].duration);
+
+  var t = p.threads[2];
+  var subRow = t.subRows[0];
+  assertEquals('b', subRow[0].title);
+  assertEquals(0.001, subRow[0].start);
+  assertEquals(0.001, subRow[0].duration);
+
+  // 0.00345 instead of 0.003 because TimelineModel bloats the world range by
+  // 15%.
+  assertEquals(-0.00045, m.minTimestamp);
+  assertEquals(0.00345, m.maxTimestamp);
+
+}
 
 function testNestedAutoclosing() {
   var events = [