cc: Simplify task and its derived classes.

cc/raster/task_graph_runner.h

Index: cc/raster/task_graph_runner.h
diff --git a/cc/raster/task_graph_runner.h b/cc/raster/task_graph_runner.h
index 23094ef5a7ef3c81a6cae0fbde931c57c11efe98..c81e7241bb571c39a31d24495b93fc49f7863478 100644
--- a/cc/raster/task_graph_runner.h
+++ b/cc/raster/task_graph_runner.h
@@ -16,37 +16,12 @@
 #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
@@ -59,7 +34,7 @@ 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)
@@ -68,7 +43,7 @@ struct CC_EXPORT TaskGraph {
           priority(priority),
           dependencies(dependencies) {}
 
-    Task* task;
+    DependencyTask* task;
     uint16_t category;
     uint16_t priority;
     uint32_t dependencies;
@@ -77,11 +52,11 @@ struct CC_EXPORT TaskGraph {
   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();
@@ -159,8 +134,9 @@ class CC_EXPORT TaskGraphRunner {
   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() {}
@@ -169,7 +145,7 @@ class CC_EXPORT 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)),
@@ -216,7 +192,7 @@ class DependentIterator {
 
  private:
   TaskGraph* graph_;
-  const Task* task_;
+  const DependencyTask* task_;
   size_t current_index_;
   TaskGraph::Node* current_node_;
 };