Move the Mac Task Manager to the new backend code.

chrome/browser/task_management/task_manager_tester.h

Index: chrome/browser/task_management/task_manager_tester.h
diff --git a/chrome/browser/task_management/task_manager_tester.h b/chrome/browser/task_management/task_manager_tester.h
index be9964724615b57927e75198d47d42a30834ebff..bc0297eccf6b1fa0290d6cf9b6e0634f8a3511cc 100644
--- a/chrome/browser/task_management/task_manager_tester.h
+++ b/chrome/browser/task_management/task_manager_tester.h
@@ -15,7 +15,7 @@
 
 namespace task_management {
 
-// An adapter that abstracts away the difference of old vs. new task manager.
+// An adapter to simplify testing the task manager.
 class TaskManagerTester {

[afakhry, 2016/08/02 16:41:33]

Maybe this adapter isn't needed anymore, but that's certainly for a later CL.

[Avi (use Gerrit), 2016/08/02 17:39:44]

Acknowledged.

[ncarter (slow), 2016/08/02 19:49:36]

I think it's fine to leave this mostly intact. We need some friend code to do
the model-getting and to interpose on the table model observer, and we need
GetColumnValue so that WaitForTaskManagerStatToExceed works properly. So we need
some test code here.

The main thing we could do would be to make this class nonvirtual, and merge
TaskManagerTester and TaskManagerTesterImpl. I'd approve that CL, but I'm not
sure it actually improves the code other than reducing the line count slightly.

[Avi (use Gerrit), 2016/08/02 20:06:56]

For followup, if nothing else. This CL is big enough.

  public:
   using ColumnSpecifier = browsertest_util::ColumnSpecifier;
@@ -26,9 +26,6 @@ class TaskManagerTester {
   static std::unique_ptr<TaskManagerTester> Create(
       const base::Closure& callback);
 
-  // If using a legacy task manager, refresh the model.
-  static void MaybeRefreshLegacyInstance();
-
   virtual ~TaskManagerTester() {}
 
   // Get the number of rows currently in the task manager.
@@ -54,11 +51,6 @@ class TaskManagerTester {
   // Gets the start index and length of the group to which the task at
   // |row_index| belongs.
   virtual void GetRowsGroupRange(int row, int* out_start, int* out_length) = 0;
-
- private:
-  // Always creates a tester for the non-legacy TaskManager.
-  static std::unique_ptr<TaskManagerTester> CreateDefault(
-      const base::Closure& callback);
 };
 
 }  // namespace task_management