Revert of cc: Add image decode queue functionality to image manager.

cc/tiles/image_controller.cc

Index: cc/tiles/image_controller.cc
diff --git a/cc/tiles/image_controller.cc b/cc/tiles/image_controller.cc
index f0d1bb9666c9cde5de93e7879041193d1e74851f..9572956864817d9a69dd6e45dbb93802b043e7f3 100644
--- a/cc/tiles/image_controller.cc
+++ b/cc/tiles/image_controller.cc
@@ -4,122 +4,15 @@
 
 #include "cc/tiles/image_controller.h"
 
-#include "base/bind.h"
-#include "base/task_scheduler/post_task.h"
-#include "base/task_scheduler/task_traits.h"
-#include "base/threading/thread_restrictions.h"
-#include "base/trace_event/trace_event.h"
-#include "cc/base/completion_event.h"
-#include "cc/tiles/tile_task_manager.h"
-
 namespace cc {
 
-ImageController::ImageDecodeRequestId
-    ImageController::s_next_image_decode_queue_id_ = 1;
-
-ImageController::ImageController(
-    base::SequencedTaskRunner* origin_task_runner,
-    scoped_refptr<base::SequencedTaskRunner> worker_task_runner)
-    : origin_task_runner_(origin_task_runner),
-      worker_task_runner_(std::move(worker_task_runner)),
-      weak_ptr_factory_(this) {}
-
-ImageController::~ImageController() {
-  StopWorkerTasks();
-}
-
-void ImageController::StopWorkerTasks() {
-  // We can't have worker threads without a cache_ or a worker_task_runner_, so
-  // terminate early.
-  if (!cache_ || !worker_task_runner_)
-    return;
-
-  // Abort all tasks that are currently scheduled to run (we'll wait for them to
-  // finish next).
-  {
-    base::AutoLock hold(lock_);
-    abort_tasks_ = true;
-  }
-
-  // Post a task that will simply signal a completion event to ensure that we
-  // "flush" any scheduled tasks (they will abort).
-  CompletionEvent completion_event;
-  worker_task_runner_->PostTask(
-      FROM_HERE, base::Bind([](CompletionEvent* event) { event->Signal(); },
-                            base::Unretained(&completion_event)));
-  completion_event.Wait();
-
-  // Reset the abort flag so that new tasks can be scheduled.
-  {
-    base::AutoLock hold(lock_);
-    abort_tasks_ = false;
-  }
-
-  // Now that we flushed everything, if there was a task running and it
-  // finished, it would have posted a completion callback back to the compositor
-  // thread. We don't want that, so invalidate the weak ptrs again. Note that
-  // nothing can start running between wait and this invalidate, since it would
-  // only run on the current (compositor) thread.
-  weak_ptr_factory_.InvalidateWeakPtrs();
-
-  // Now, begin cleanup.
-
-  // Unlock all of the locked images (note that this vector would only be
-  // populated if we actually need to unref the image.
-  for (auto image_pair : requested_locked_images_)
-    cache_->UnrefImage(image_pair.second);
-  requested_locked_images_.clear();
-
-  // Now, complete the tasks that already ran but haven't completed. These would
-  // be posted in the run loop, but since we invalidated the weak ptrs, we need
-  // to run everything manually.
-  for (auto& request_to_complete : requests_needing_completion_) {
-    ImageDecodeRequestId id = request_to_complete.first;
-    ImageDecodeRequest& request = request_to_complete.second;
-
-    // The task (if one exists) would have run already, so we just need to
-    // complete it.
-    if (request.task)
-      request.task->DidComplete();
-
-    // Issue the callback, and unref the image immediately. This is so that any
-    // code waiting on the callback can proceed, although we're breaking the
-    // promise of having this image decoded. This is unfortunate, but it seems
-    // like the least complexity to process an image decode controller becoming
-    // nullptr.
-    request.callback.Run(id);
-    if (request.need_unref)
-      cache_->UnrefImage(request.draw_image);
-  }
-  requests_needing_completion_.clear();
-
-  // Finally, complete all of the tasks that never started running. This is
-  // similar to the |requests_needing_completion_|, but happens at a different
-  // stage in the pipeline.
-  for (auto& request_pair : image_decode_queue_) {
-    ImageDecodeRequestId id = request_pair.first;
-    ImageDecodeRequest& request = request_pair.second;
-
-    if (request.task) {
-      // This task may have run via a different request, so only cancel it if
-      // it's "new". That is, the same task could have been referenced by
-      // several different image deque requests for the same image.
-      if (request.task->state().IsNew())
-        request.task->state().DidCancel();
-      request.task->DidComplete();
-    }
-    // Run the callback and unref the image.
-    request.callback.Run(id);
-    cache_->UnrefImage(request.draw_image);
-  }
-  image_decode_queue_.clear();
-}
+ImageController::ImageController() = default;
+ImageController::~ImageController() = default;
 
 void ImageController::SetImageDecodeCache(ImageDecodeCache* cache) {
   if (!cache) {
     SetPredecodeImages(std::vector<DrawImage>(),
                        ImageDecodeCache::TracingInfo());
-    StopWorkerTasks();
   }
   cache_ = cache;
 }
@@ -163,155 +56,4 @@
   return new_tasks;
 }
 
-ImageController::ImageDecodeRequestId ImageController::QueueImageDecode(
-    sk_sp<const SkImage> image,
-    const ImageDecodedCallback& callback) {
-  // We must not receive any image requests if we have no worker.
-  CHECK(worker_task_runner_);
-
-  // Generate the next id.
-  ImageDecodeRequestId id = s_next_image_decode_queue_id_++;
-
-  DCHECK(image);
-  auto image_bounds = image->bounds();
-  DrawImage draw_image(std::move(image), image_bounds, kNone_SkFilterQuality,
-                       SkMatrix::I());
-
-  // Get the tasks for this decode.
-  scoped_refptr<TileTask> task;
-  bool need_unref =
-      cache_->GetOutOfRasterDecodeTaskForImageAndRef(draw_image, &task);
-  // If we don't need to unref this, we don't actually have a task.
-  DCHECK(need_unref || !task);
-
-  // Schedule the task and signal that there is more work.
-  base::AutoLock hold(lock_);
-  image_decode_queue_[id] =
-      ImageDecodeRequest(id, draw_image, callback, std::move(task), need_unref);
-
-  // If this is the only image decode request, schedule a task to run.
-  // Otherwise, the task will be scheduled in the previou task's completion.
-  if (image_decode_queue_.size() == 1) {
-    // Post a worker task.
-    worker_task_runner_->PostTask(
-        FROM_HERE,
-        base::Bind(&ImageController::ProcessNextImageDecodeOnWorkerThread,
-                   base::Unretained(this)));
-  }
-
-  return id;
-}
-
-void ImageController::UnlockImageDecode(ImageDecodeRequestId id) {
-  // If the image exists, ie we actually need to unlock it, then do so.
-  auto it = requested_locked_images_.find(id);
-  if (it == requested_locked_images_.end())
-    return;
-
-  UnrefImages({it->second});
-  requested_locked_images_.erase(it);
-}
-
-void ImageController::ProcessNextImageDecodeOnWorkerThread() {
-  TRACE_EVENT0("cc", "ImageController::ProcessNextImageDecodeOnWorkerThread");
-  ImageDecodeRequest decode;
-  {
-    base::AutoLock hold(lock_);
-
-    // If we don't have any work, abort.
-    if (image_decode_queue_.empty() || abort_tasks_)
-      return;
-
-    // Take the next request from the queue.
-    auto decode_it = image_decode_queue_.begin();
-    DCHECK(decode_it != image_decode_queue_.end());
-    decode = std::move(decode_it->second);
-    image_decode_queue_.erase(decode_it);
-
-    // Notify that the task will need completion. Note that there are two cases
-    // where we process this. First, we might complete this task as a response
-    // to the posted task below. Second, we might complete it in
-    // StopWorkerTasks(). In either case, the task would have already run
-    // (either post task happens after running, or the thread was already joined
-    // which means the task ran). This means that we can put the decode into
-    // |requests_needing_completion_| here before actually running the task.
-    requests_needing_completion_[decode.id] = decode;
-  }
-
-  // Run the task if we need to run it. If the task state isn't new, then
-  // there is another task that is responsible for finishing it and cleaning
-  // up (and it already ran); we just need to post a completion callback.
-  // Note that the other tasks's completion will also run first, since the
-  // requests are ordered. So, when we process this task's completion, we
-  // won't actually do anything with the task and simply issue the callback.
-  if (decode.task && decode.task->state().IsNew()) {
-    decode.task->state().DidSchedule();
-    decode.task->state().DidStart();
-    decode.task->RunOnWorkerThread();
-    decode.task->state().DidFinish();
-  }
-  origin_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&ImageController::ImageDecodeCompleted,
-                            weak_ptr_factory_.GetWeakPtr(), decode.id));
-}
-
-void ImageController::ImageDecodeCompleted(ImageDecodeRequestId id) {
-  ImageDecodedCallback callback;
-  {
-    base::AutoLock hold(lock_);
-
-    auto request_it = requests_needing_completion_.find(id);
-    DCHECK(request_it != requests_needing_completion_.end());
-    id = request_it->first;
-    ImageDecodeRequest& request = request_it->second;
-
-    // If we need to unref this decode, then we have to put it into the locked
-    // images vector.
-    if (request.need_unref)
-      requested_locked_images_[id] = std::move(request.draw_image);
-
-    // If we have a task that isn't completed yet, we need to complete it.
-    if (request.task && !request.task->HasCompleted()) {
-      request.task->OnTaskCompleted();
-      request.task->DidComplete();
-    }
-    // Finally, save the callback so we can run it without the lock, and erase
-    // the request from |requests_needing_completion_|.
-    callback = std::move(request.callback);
-    requests_needing_completion_.erase(request_it);
-  }
-
-  // Post another task to run.
-  worker_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&ImageController::ProcessNextImageDecodeOnWorkerThread,
-                 base::Unretained(this)));
-
-  // Finally run the requested callback.
-  callback.Run(id);
-}
-
-ImageController::ImageDecodeRequest::ImageDecodeRequest() = default;
-ImageController::ImageDecodeRequest::ImageDecodeRequest(
-    ImageDecodeRequestId id,
-    const DrawImage& draw_image,
-    const ImageDecodedCallback& callback,
-    scoped_refptr<TileTask> task,
-    bool need_unref)
-    : id(id),
-      draw_image(draw_image),
-      callback(callback),
-      task(std::move(task)),
-      need_unref(need_unref) {}
-ImageController::ImageDecodeRequest::ImageDecodeRequest(
-    ImageDecodeRequest&& other) = default;
-ImageController::ImageDecodeRequest::ImageDecodeRequest(
-    const ImageDecodeRequest& other) = default;
-ImageController::ImageDecodeRequest::~ImageDecodeRequest() = default;
-
-ImageController::ImageDecodeRequest& ImageController::ImageDecodeRequest::
-operator=(ImageDecodeRequest&& other) = default;
-ImageController::ImageDecodeRequest& ImageController::ImageDecodeRequest::
-operator=(const ImageDecodeRequest& other) = default;
-
 }  // namespace cc