mash: Migrate wallpaper controllers to ash/common.

components/wallpaper/wallpaper_resizer.cc

Index: components/wallpaper/wallpaper_resizer.cc
diff --git a/components/wallpaper/wallpaper_resizer.cc b/components/wallpaper/wallpaper_resizer.cc
index 47e391d5380a53dab0adfa58136feaf03dd98ebd..44be4218d38b696ad7ff154cc34e08d3699c0c01 100644
--- a/components/wallpaper/wallpaper_resizer.cc
+++ b/components/wallpaper/wallpaper_resizer.cc
@@ -7,15 +7,12 @@
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
-#include "base/threading/sequenced_worker_pool.h"
-#include "base/threading/worker_pool.h"
+#include "base/task_runner.h"
 #include "components/wallpaper/wallpaper_resizer_observer.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "ui/gfx/image/image_skia_rep.h"
 #include "ui/gfx/skia_util.h"
 
-using base::SequencedWorkerPool;
-
 namespace wallpaper {
 namespace {
 
@@ -30,8 +27,8 @@ void Resize(SkBitmap orig_bitmap,
             const gfx::Size& target_size,
             WallpaperLayout layout,
             SkBitmap* resized_bitmap_out,
-            SequencedWorkerPool* worker_pool) {
-  DCHECK(worker_pool->RunsTasksOnCurrentThread());
+            base::TaskRunner* task_runner) {
+  DCHECK(task_runner->RunsTasksOnCurrentThread());
   SkBitmap new_bitmap = orig_bitmap;
 
   const int orig_width = orig_bitmap.width();
@@ -107,12 +104,12 @@ uint32_t WallpaperResizer::GetImageId(const gfx::ImageSkia& image) {
 WallpaperResizer::WallpaperResizer(const gfx::ImageSkia& image,
                                    const gfx::Size& target_size,
                                    WallpaperLayout layout,
-                                   base::SequencedWorkerPool* worker_pool_ptr)
+                                   base::TaskRunner* task_runner)
     : image_(image),
       original_image_id_(GetImageId(image_)),
       target_size_(target_size),
       layout_(layout),
-      worker_pool_(worker_pool_ptr),
+      task_runner_(task_runner),
       weak_ptr_factory_(this) {
   image_.MakeThreadSafe();
 }
@@ -122,11 +119,11 @@ WallpaperResizer::~WallpaperResizer() {
 
 void WallpaperResizer::StartResize() {
   SkBitmap* resized_bitmap = new SkBitmap;
-  scoped_refptr<SequencedWorkerPool> worker_pool_refptr(worker_pool_);
-  if (!worker_pool_->PostTaskAndReply(
+  scoped_refptr<base::TaskRunner> task_runner_refptr(task_runner_);

[James Cook, 2016/09/07 21:27:05]

I see you haven't changed this, but just for my knowledge... Is this a common
pattern with refptrs? It seems odd that we cache a raw pointer in |task_runner_|
then turn around later and make a refptr out of it to bump its refcount during
the task processing. It kinda seems like either the pointer should outline
WallpaperResizer, and hence shouldn't need refcounting, or it should be stored
in a refptr member variable.

[msw, 2016/09/07 22:28:24]

I'm also not too familiar with this pattern or the reasoning behind it;
WallpaperResizer is very short lived and should outlive the task runner, so your
suggestion makes sense. I gave it a shot.

+  if (!task_runner_->PostTaskAndReply(
           FROM_HERE,
           base::Bind(&Resize, *image_.bitmap(), target_size_, layout_,
-                     resized_bitmap, base::RetainedRef(worker_pool_refptr)),
+                     resized_bitmap, base::RetainedRef(task_runner_refptr)),
           base::Bind(&WallpaperResizer::OnResizeFinished,
                      weak_ptr_factory_.GetWeakPtr(),
                      base::Owned(resized_bitmap)))) {