Fix task groups to always be self-consistent.

chrome/browser/ui/task_manager/task_manager_table_model.cc

Index: chrome/browser/ui/task_manager/task_manager_table_model.cc
diff --git a/chrome/browser/ui/task_manager/task_manager_table_model.cc b/chrome/browser/ui/task_manager/task_manager_table_model.cc
index d921daa251a020ca5ad11d04971afc14ed8afd12..874569a6f2d96d1e271be460593b0347925679a1 100644
--- a/chrome/browser/ui/task_manager/task_manager_table_model.cc
+++ b/chrome/browser/ui/task_manager/task_manager_table_model.cc
@@ -562,17 +562,20 @@ int TaskManagerTableModel::CompareValues(int row1,
 void TaskManagerTableModel::GetRowsGroupRange(int row_index,
                                               int* out_start,
                                               int* out_length) {
+  const base::ProcessId process_id =
+      observed_task_manager()->GetProcessId(tasks_[row_index]);
   int i = row_index;
-  for ( ; i >= 0; --i) {
-    if (IsTaskFirstInGroup(i))
-      break;
+  int limit = row_index + 1;
+  while (i > 0 &&
+         observed_task_manager()->GetProcessId(tasks_[i - 1]) == process_id) {
+    --i;
+  }
+  while (limit < RowCount() &&
+         observed_task_manager()->GetProcessId(tasks_[limit]) == process_id) {
+    ++limit;
   }
-
-  CHECK_GE(i, 0);
-
   *out_start = i;
-  *out_length = observed_task_manager()->GetNumberOfTasksOnSameProcess(
-      tasks_[row_index]);
+  *out_length = limit - i;
 }
 
 void TaskManagerTableModel::OnTaskAdded(TaskId id) {