Improving the process model extension API

chrome/browser/task_manager/task_manager.h

Index: chrome/browser/task_manager/task_manager.h
diff --git a/chrome/browser/task_manager/task_manager.h b/chrome/browser/task_manager/task_manager.h
index fe88a0905a331b1fe9b843d6be1fdbde37c4f941..866b075534a1c01e0469f265cf02d435e0058e22 100644
--- a/chrome/browser/task_manager/task_manager.h
+++ b/chrome/browser/task_manager/task_manager.h
@@ -255,6 +255,11 @@ class TaskManagerModelObserver {
   // Invoked when a range of items has been removed.
   virtual void OnItemsRemoved(int start, int length) = 0;
 
+  // Invoked when a range of items is to be immediately removed. It differs
+  // from OnItemsRemoved by the fact that the item is still in the task manager,
+  // so it can be queried for and found.
+  virtual void OnItemsToBeRemoved(int start, int length) {}
+
   // Invoked when the initialization of the model has been finished and
   // periodical updates is started. The first periodical update will be done
   // in a few seconds. (depending on platform)
@@ -281,6 +286,7 @@ class TaskManagerModel : public base::RefCountedThreadSafe<TaskManagerModel> {
   int64 GetNetworkUsage(int index) const;
   double GetCPUUsage(int index) const;
   int GetProcessId(int index) const;
+  base::ProcessHandle GetProcess(int index) const;
   int GetResourceUniqueId(int index) const;
   // Returns the index of resource that has the given |unique_id|. Returns -1 if
   // no resouce has the |unique_id|.
@@ -334,6 +340,10 @@ class TaskManagerModel : public base::RefCountedThreadSafe<TaskManagerModel> {
   // resource for the given row isn't a renderer.
   bool GetV8Memory(int index, size_t* result) const;
 
+  // Gets the amount of memory used for javascript. Returns false if the
+  // resource for the given row isn't a renderer.
+  bool GetV8MemoryUsed(int index, size_t* result) const;
+
   // Returns true if resource for the given row can be activated.
   bool CanActivate(int index) const;
 
@@ -397,6 +407,9 @@ class TaskManagerModel : public base::RefCountedThreadSafe<TaskManagerModel> {
   void StartUpdating();
   void StopUpdating();
 
+  void StartListening();

[Charlie Reis, 2012/04/27 22:01:56]

These should have comments to explain what they're for and how they're different
from Start/StopUpdating.

[nasko, 2012/04/30 18:05:19]

Done.

+  void StopListening();
+
   void Clear();  // Removes all items.
 
   // Sends OnModelChanged() to all observers to inform them of significant
@@ -430,6 +443,11 @@ class TaskManagerModel : public base::RefCountedThreadSafe<TaskManagerModel> {
     STOPPING       // A update task is pending and it should stop the update.
   };
 
+  enum ListenState {

[Charlie Reis, 2012/04/27 22:01:56]

Why not a is_listeneing_ boolean?  With UpdateState, they needed 3 values.

[nasko, 2012/04/30 18:05:19]

I initially started with different states. You are right that we can do it with
a boolean. Changed.

+    LISTEN_OFF = 0,
+    LISTEN_ON
+  };
+
   // This struct is used to exchange information between the io and ui threads.
   struct BytesReadParam {
     BytesReadParam(int origin_pid,
@@ -542,9 +560,17 @@ class TaskManagerModel : public base::RefCountedThreadSafe<TaskManagerModel> {
   // StopUpdating.
   int update_requests_;
 
+  // How many calls to StartListening have been made without matching calls to
+  // StopListening.
+  int listen_requests_;
+
   // Whether we are currently in the process of updating.
   UpdateState update_state_;
 
+  // Whether we have resource managers listening for events and maintaining
+  // the TaskManagerModel resources.
+  ListenState listen_state_;
+
   // A salt lick for the goats.
   uint64 goat_salt_;