cc: Remove ScheduleOnOriginThread() and CompleteOnOriginThread().

cc/raster/task.cc

Index: cc/raster/task.cc
diff --git a/cc/raster/task.cc b/cc/raster/task.cc
index 4f26d12ba4495bef070161fd6b48569654755c51..9dc9c59ccbc1a41e0ad9118a4d7a0cfe4bc1e176 100644
--- a/cc/raster/task.cc
+++ b/cc/raster/task.cc
@@ -13,6 +13,8 @@ TaskState::TaskState() : value_(Value::NEW) {}
 TaskState::~TaskState() {
   DCHECK(value_ != Value::RUNNING)
       << "Running task should never get destroyed.";
+  // TODO(prashant.n): Remove NEW, once all the tests follow the task life
+  // cycle correctly. Few tests still do not take care of task states.

[vmpstr, 2016/05/21 00:02:14]

I'd prefer that we fix the tests instead of adding this TODO. Are there a lot of
cases? How difficult is it to fix them?

[prashant.n, 2016/05/21 00:33:53]

Few testcases I've fixed in https://codereview.chromium.org/1997743002/. Now
only few have remained  related to RasterBufferProvider tests.

I'll submit separate patch for this.

   DCHECK(value_ == Value::NEW || value_ == Value::FINISHED ||
          value_ == Value::CANCELED)
       << "Task, if scheduled, should get concluded either in FINISHED or "
@@ -26,9 +28,11 @@ bool TaskState::IsScheduled() const {
 bool TaskState::IsRunning() const {
   return value_ == Value::RUNNING;
 }
+
 bool TaskState::IsFinished() const {
   return value_ == Value::FINISHED;
 }
+
 bool TaskState::IsCanceled() const {
   return value_ == Value::CANCELED;
 }
@@ -58,7 +62,7 @@ void TaskState::DidFinish() {
 
 void TaskState::DidCancel() {
   DCHECK(value_ == Value::NEW || value_ == Value::SCHEDULED)
-      << "Task should be scheduled and not running to get canceled.";
+      << "Task should be either new or scheduled to get canceled.";
   value_ = Value::CANCELED;
 }