TaskManager: when shown or activated, select the last active tab.

chrome/browser/ui/task_manager/task_manager_table_model.h

Index: chrome/browser/ui/task_manager/task_manager_table_model.h
diff --git a/chrome/browser/ui/task_manager/task_manager_table_model.h b/chrome/browser/ui/task_manager/task_manager_table_model.h
index a983c07e44342bd70c79e5d70535ab3ea2415101..084a543b8049150ca5c003ee586b9a33d5439e39 100644
--- a/chrome/browser/ui/task_manager/task_manager_table_model.h
+++ b/chrome/browser/ui/task_manager/task_manager_table_model.h
@@ -14,6 +14,10 @@
 #include "chrome/browser/task_management/task_manager_observer.h"
 #include "ui/base/models/table_model.h"
 
+namespace content {
+class WebContents;
+}
+
 namespace task_management {
 
 class TaskManagerValuesStringifier;
@@ -99,6 +103,11 @@ class TaskManagerTableModel
 
   void ToggleColumnVisibility(int column_id);
 
+  // Returns the row index corresponding to a particular WebContents. Returns -1
+  // if |web_contents| is nullptr, or is not currently found in the model (for
+  // example, if the tab is currently crashed).
+  int GetRowForWebContents(content::WebContents* web_contents);
+
  private:
   friend class TaskManagerTesterImpl;