cc: Simplify task and its derived classes.

cc/raster/task_graph_runner.h

 // Copyright 2014 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_RASTER_TASK_GRAPH_RUNNER_H_
 #define CC_RASTER_TASK_GRAPH_RUNNER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
 #include <map>
 #include <vector>
 
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
+#include "cc/raster/dependency_task.h"
 
 namespace cc {
 
 class TaskGraphRunner;
 
-// A task which can be run by a TaskGraphRunner. To run a Task, it should be
-// inserted into a TaskGraph, which can then be scheduled on the
-// TaskGraphRunner.
-class CC_EXPORT Task : public base::RefCountedThreadSafe<Task> {
- public:
-  typedef std::vector<scoped_refptr<Task>> Vector;
-
-  // Subclasses should implement this method. RunOnWorkerThread may be called
-  // on any thread, and subclasses are responsible for locking and thread
-  // safety.
-  virtual void RunOnWorkerThread() = 0;
-
-  void WillRun();
-  void DidRun();
-  bool HasFinishedRunning() const;
-
- protected:
-  friend class base::RefCountedThreadSafe<Task>;
-
-  Task();
-  virtual ~Task();
-
-  bool will_run_;
-  bool did_run_;
-};
-
 // A task dependency graph describes the order in which to execute a set
 // of tasks. Dependencies are represented as edges. Each node is assigned
 // a category, a priority and a run count that matches the number of
 // dependencies. Priority range from 0 (most favorable scheduling) to UINT16_MAX
 // (least favorable). Categories range from 0 to UINT16_MAX. It is up to the
 // implementation and its consumer to determine the meaning (if any) of a
 // category. A TaskGraphRunner implementation may chose to prioritize certain
 // categories over others, regardless of the individual priorities of tasks.
 struct CC_EXPORT TaskGraph {
   struct Node {
     typedef std::vector<Node> Vector;
 
-    Node(Task* task,
+    Node(DependencyTask* task,
          uint16_t category,
          uint16_t priority,
          uint32_t dependencies)
         : task(task),
           category(category),
           priority(priority),
           dependencies(dependencies) {}
 
-    Task* task;
+    DependencyTask* task;
     uint16_t category;
     uint16_t priority;
     uint32_t dependencies;
   };
 
   struct Edge {
     typedef std::vector<Edge> Vector;
 
-    Edge(const Task* task, Task* dependent)
+    Edge(const DependencyTask* task, DependencyTask* dependent)
         : task(task), dependent(dependent) {}
 
-    const Task* task;
-    Task* dependent;
+    const DependencyTask* task;
+    DependencyTask* dependent;
   };
 
   TaskGraph();
   TaskGraph(const TaskGraph& other);
   ~TaskGraph();
 
   void Swap(TaskGraph* other);
   void Reset();
 
   Node::Vector nodes;
@@ skipping 57 matching lines @@
   // longer needed will be canceled unless already running. Canceled tasks are
   // moved to |completed_tasks| without being run. The result is that once
   // scheduled, a task is guaranteed to end up in the |completed_tasks| queue
   // even if it later gets canceled by another call to ScheduleTasks().
   virtual void ScheduleTasks(NamespaceToken token, TaskGraph* graph) = 0;
 
   // Wait for all scheduled tasks to finish running.
   virtual void WaitForTasksToFinishRunning(NamespaceToken token) = 0;
 
   // Collect all completed tasks in |completed_tasks|.
-  virtual void CollectCompletedTasks(NamespaceToken token,
-                                     Task::Vector* completed_tasks) = 0;
+  virtual void CollectCompletedTasks(
+      NamespaceToken token,
+      DependencyTask::Vector* completed_tasks) = 0;
 
  protected:
   virtual ~TaskGraphRunner() {}
 };
 
 // Helper class for iterating over all dependents of a task.
 class DependentIterator {
  public:
-  DependentIterator(TaskGraph* graph, const Task* task)
+  DependentIterator(TaskGraph* graph, const DependencyTask* task)
       : graph_(graph),
         task_(task),
         current_index_(static_cast<size_t>(-1)),
         current_node_(NULL) {
     ++(*this);
   }
 
   TaskGraph::Node& operator->() const {
     DCHECK_LT(current_index_, graph_->edges.size());
     DCHECK_EQ(graph_->edges[current_index_].task, task_);
@@ skipping 26 matching lines @@
     DCHECK(it != graph_->nodes.end());
     current_node_ = &(*it);
 
     return *this;
   }
 
   operator bool() const { return current_index_ < graph_->edges.size(); }
 
  private:
   TaskGraph* graph_;
-  const Task* task_;
+  const DependencyTask* task_;
   size_t current_index_;
   TaskGraph::Node* current_node_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RASTER_TASK_GRAPH_RUNNER_H_