cc: Add TaskGraphRunner sub-namespaces with task concurrency limits.

cc/resources/tile_task_worker_pool.cc

Index: cc/resources/tile_task_worker_pool.cc
diff --git a/cc/resources/tile_task_worker_pool.cc b/cc/resources/tile_task_worker_pool.cc
index 277538648ba9b22fb0e56cceaf4ea716a9985052..fa2b350110d4a26520586a2d269c32a737c171f5 100644
--- a/cc/resources/tile_task_worker_pool.cc
+++ b/cc/resources/tile_task_worker_pool.cc
@@ -163,11 +163,14 @@ void TileTaskWorkerPool::ScheduleTasksOnOriginThread(TileTaskClient* client,
 void TileTaskWorkerPool::InsertNodeForTask(TaskGraph* graph,
                                            TileTask* task,
                                            unsigned priority,
-                                           size_t dependencies) {
+                                           size_t dependencies,
+                                           int sub_namespace,
+                                           int max_concurrent_tasks) {
   DCHECK(std::find_if(graph->nodes.begin(), graph->nodes.end(),
                       TaskGraph::Node::TaskComparator(task)) ==
          graph->nodes.end());
-  graph->nodes.push_back(TaskGraph::Node(task, priority, dependencies));
+  graph->nodes.push_back(TaskGraph::Node(task, priority, dependencies,
+                                         sub_namespace, max_concurrent_tasks));
 }
 
 // static
@@ -175,7 +178,9 @@ void TileTaskWorkerPool::InsertNodesForRasterTask(
     TaskGraph* graph,
     RasterTask* raster_task,
     const ImageDecodeTask::Vector& decode_tasks,
-    unsigned priority) {
+    unsigned priority,
+    int sub_namespace,
+    int max_concurrent_tasks) {
   size_t dependencies = 0u;
 
   // Insert image decode tasks.
@@ -194,12 +199,14 @@ void TileTaskWorkerPool::InsertNodesForRasterTask(
         std::find_if(graph->nodes.begin(), graph->nodes.end(),
                      TaskGraph::Node::TaskComparator(decode_task));
     if (decode_it == graph->nodes.end())
-      InsertNodeForTask(graph, decode_task, priority, 0u);
+      InsertNodeForTask(graph, decode_task, priority, 0u, kDefaultSubNamespace,

[danakj, 2015/02/23 18:45:01]

when using the defaults can you leave a comment why?

+                        kDefaultMaxConcurrentTasks);
 
     graph->edges.push_back(TaskGraph::Edge(decode_task, raster_task));
   }
 
-  InsertNodeForTask(graph, raster_task, priority, dependencies);
+  InsertNodeForTask(graph, raster_task, priority, dependencies, sub_namespace,
+                    max_concurrent_tasks);
 }
 
 static bool IsSupportedPlaybackToMemoryFormat(ResourceFormat format) {