cc: Replace RasterTaskStateMap with a vector and brute force search instead of hash map lookups.

cc/resources/pixel_buffer_raster_worker_pool.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_RESOURCES_PIXEL_BUFFER_RASTER_WORKER_POOL_H_
 #define CC_RESOURCES_PIXEL_BUFFER_RASTER_WORKER_POOL_H_
 
-#include <deque>
+#include <vector>
 
-#include "base/containers/hash_tables.h"
 #include "cc/resources/raster_worker_pool.h"
 
-#if defined(COMPILER_GCC)
-namespace BASE_HASH_NAMESPACE {
-template <>
-struct hash<cc::internal::WorkerPoolTask*> {
-  size_t operator()(cc::internal::WorkerPoolTask* ptr) const {
-    return hash<size_t>()(reinterpret_cast<size_t>(ptr));
-  }
-};
-}  // namespace BASE_HASH_NAMESPACE
-#endif  // COMPILER
-
 namespace cc {
 
 class CC_EXPORT PixelBufferRasterWorkerPool : public RasterWorkerPool {
  public:
   virtual ~PixelBufferRasterWorkerPool();
 
   static scoped_ptr<RasterWorkerPool> Create(
       ResourceProvider* resource_provider,
       size_t max_transfer_buffer_usage_bytes);
 
@@ skipping 10 matching lines @@
   virtual void ReleaseCanvasForRaster(internal::WorkerPoolTask* task,
                                       const Resource* resource) OVERRIDE;
 
  protected:
   PixelBufferRasterWorkerPool(internal::TaskGraphRunner* task_graph_runner,
                               ResourceProvider* resource_provider,
                               size_t max_transfer_buffer_usage_bytes);
 
  private:
   struct RasterTaskState {
-    RasterTaskState()
-        : type(UNSCHEDULED), resource(NULL), required_for_activation(false) {}
+    class TaskComparator {

[vmpstr, 2014/02/21 18:39:41]

I know this is consistent with other classes in task graph runner / worker pool
system, but is there a better name for this class? TaskComparator to me means
something that compares two arbitrary tasks to determine which one is "better"
or something..

This is more like a TaskFinder where it only returns true if the passed argument
matches the constructor argument. I don't know, this is mostly a big nit but
feel free to leave it as is, since I don't have any good suggestions.

[reveman, 2014/02/22 11:32:01]

Maybe IsTask or IsTaskComparator would be better as the result is code such as:

find_if(states.begin(), states.end(), IsTask(task))

I would have to change this everywhere though so better as a follow up. 

[vmpstr, 2014/02/24 17:37:58]

IsTask or IsTaskComparator or IsTaskClosure or something all sound good to me.
As a follow up sounds good as well.

+     public:
+      explicit TaskComparator(const internal::WorkerPoolTask* task)
+          : task_(task) {}
+
+      bool operator()(const RasterTaskState& state) const {
+        return state.task == task_;
+      }
+
+     private:
+      const internal::WorkerPoolTask* task_;
+    };
+
+    typedef std::vector<RasterTaskState> Vector;
+
+    RasterTaskState(internal::WorkerPoolTask* task,
+                    bool required_for_activation)
+        : type(UNSCHEDULED),
+          task(task),
+          resource(NULL),
+          required_for_activation(required_for_activation) {}
 
     RasterTaskState& set_completed() {
       type = COMPLETED;
       return *this;
     }
     RasterTaskState& set_required_for_activation(bool is_required) {
       required_for_activation = is_required;
       return *this;
     }
 
     enum { UNSCHEDULED, SCHEDULED, UPLOADING, COMPLETED } type;
+    internal::WorkerPoolTask* task;
     const Resource* resource;
     bool required_for_activation;
   };
-  typedef internal::WorkerPoolTask* RasterTaskMapKey;
-  typedef base::hash_map<RasterTaskMapKey, RasterTaskState> RasterTaskStateMap;
 
   // Overridden from RasterWorkerPool:
   virtual void OnRasterTasksFinished() OVERRIDE;
   virtual void OnRasterTasksRequiredForActivationFinished() OVERRIDE;
 
   void FlushUploads();
   void CheckForCompletedUploads();
   void ScheduleCheckForCompletedRasterTasks();
   void OnCheckForCompletedRasterTasks();
   void CheckForCompletedRasterTasks();
   void ScheduleMoreTasks();
   unsigned PendingRasterTaskCount() const;
   bool HasPendingTasks() const;
   bool HasPendingTasksRequiredForActivation() const;
   void CheckForCompletedWorkerPoolTasks();
 
   const char* StateName() const;
   scoped_ptr<base::Value> StateAsValue() const;
   scoped_ptr<base::Value> ThrottleStateAsValue() const;
 
   bool shutdown_;
 
   RasterTaskQueue raster_tasks_;
-  RasterTaskStateMap raster_task_states_;
+  RasterTaskState::Vector raster_task_states_;
+  RasterTaskState::Vector recycled_raster_task_states_;
   TaskDeque raster_tasks_with_pending_upload_;
-  TaskDeque completed_raster_tasks_;
-  TaskDeque completed_image_decode_tasks_;
+  TaskVector completed_raster_tasks_;
+  TaskVector completed_image_decode_tasks_;
 
   size_t scheduled_raster_task_count_;
   size_t raster_tasks_required_for_activation_count_;
   size_t bytes_pending_upload_;
   size_t max_bytes_pending_upload_;
   bool has_performed_uploads_since_last_flush_;
   base::TimeTicks check_for_completed_raster_tasks_time_;
   bool check_for_completed_raster_tasks_pending_;
 
   bool should_notify_client_if_no_tasks_are_pending_;
   bool should_notify_client_if_no_tasks_required_for_activation_are_pending_;
   bool raster_finished_task_pending_;
   bool raster_required_for_activation_finished_task_pending_;
 
   // Task graph used when scheduling tasks and vector used to gather
   // completed tasks.
   internal::TaskGraph graph_;
   internal::Task::Vector completed_tasks_;
 
   base::WeakPtrFactory<PixelBufferRasterWorkerPool> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PixelBufferRasterWorkerPool);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PIXEL_BUFFER_RASTER_WORKER_POOL_H_