cc: Simplify task and its derived classes.

cc/raster/task_graph_runner.cc

Index: cc/raster/task_graph_runner.cc
diff --git a/cc/raster/task_graph_runner.cc b/cc/raster/task_graph_runner.cc
index 4f1af43ad43901309131886aa2dd6d5c6de1343a..5de1db8f7b27fa6411870a527c764e026aae4f9e 100644
--- a/cc/raster/task_graph_runner.cc
+++ b/cc/raster/task_graph_runner.cc
@@ -13,28 +13,6 @@
 
 namespace cc {
 
-Task::Task() : will_run_(false), did_run_(false) {}
-
-Task::~Task() {
-  DCHECK(!will_run_);
-}
-
-void Task::WillRun() {
-  DCHECK(!will_run_);
-  DCHECK(!did_run_);
-  will_run_ = true;
-}
-
-void Task::DidRun() {
-  DCHECK(will_run_);
-  will_run_ = false;
-  did_run_ = true;
-}
-
-bool Task::HasFinishedRunning() const {
-  return did_run_;
-}
-
 TaskGraph::TaskGraph() {}
 
 TaskGraph::TaskGraph(const TaskGraph& other) = default;