arc: Do not keep track of in-flight decode requests.

chrome/browser/chromeos/arc/arc_wallpaper_handler.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chromeos/arc/arc_wallpaper_handler.h"
 
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 42 matching lines @@
   // TODO(crbug.com/618922): Register the wallpaper to Chrome OS wallpaper
   // picker. Currently the new wallpaper does not appear there. The best way to
   // make this happen seems to do the same things as wallpaper_api.cc and
   // wallpaper_private_api.cc.
 }
 
 }  // namespace
 
 // An implementation of ImageDecoder::ImageRequest that just calls back
 // ArcWallpaperHandler.
 class ArcWallpaperHandler::ImageRequestImpl

[hidehiko, 2016/07/25 19:17:20]

Optional: Now this class looks not having any important roll?
Can this be merged into enclosing class?
WDYT?

[Shuhei Takahashi, 2016/07/26 05:41:43]

Thanks, now I can implement ImageRequest in ArcWallpaperHandler.

     : public ImageDecoder::ImageRequest {
  public:
   // |handler| outlives this instance.
   explicit ImageRequestImpl(ArcWallpaperHandler* handler) : handler_(handler) {}
 
   // ImageDecoder::ImageRequest implementation.
   void OnImageDecoded(const SkBitmap& bitmap) override {
-    handler_->OnImageDecoded(this, bitmap);
+    handler_->OnImageDecoded(bitmap);
   }
-  void OnDecodeImageFailed() override { handler_->OnDecodeImageFailed(this); }
+  void OnDecodeImageFailed() override { handler_->OnDecodeImageFailed(); }
 
  private:
   ArcWallpaperHandler* const handler_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageRequestImpl);
 };
 
 ArcWallpaperHandler::ArcWallpaperHandler() = default;
 
 ArcWallpaperHandler::~ArcWallpaperHandler() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  // Cancel in-flight requests.
-  for (auto& request : inflight_requests_)
-    ImageDecoder::Cancel(request.get());
-  inflight_requests_.clear();
+  CancelInflightRequest();
 }
 
 void ArcWallpaperHandler::SetWallpaper(const std::vector<uint8_t>& jpeg_data) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   std::unique_ptr<ImageRequestImpl> request =
       base::MakeUnique<ImageRequestImpl>(this);
   // TODO(nya): Improve ImageDecoder to minimize copy.
   std::string jpeg_data_as_string(
       reinterpret_cast<const char*>(jpeg_data.data()), jpeg_data.size());
   ImageDecoder::StartWithOptions(request.get(), jpeg_data_as_string,
                                  ImageDecoder::ROBUST_JPEG_CODEC, true);
-  inflight_requests_.insert(std::move(request));
+  CancelInflightRequest();
+  inflight_request_ = std::move(request);
 }
 
-void ArcWallpaperHandler::OnImageDecoded(ImageRequestImpl* request,
-                                         const SkBitmap& bitmap) {
+void ArcWallpaperHandler::OnImageDecoded(const SkBitmap& bitmap) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  inflight_requests_.erase(base::WrapUnique(request));
+  inflight_request_.reset();
   SetBitmapAsWallpaper(bitmap);
 }
 
-void ArcWallpaperHandler::OnDecodeImageFailed(ImageRequestImpl* request) {
+void ArcWallpaperHandler::OnDecodeImageFailed() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  inflight_requests_.erase(base::WrapUnique(request));
+  inflight_request_.reset();
   LOG(ERROR) << "Failed to decode wallpaper image.";
 }
 
+void ArcWallpaperHandler::CancelInflightRequest() {
+  if (inflight_request_.get()) {

[hidehiko, 2016/07/25 19:17:20]

DCHECK_CURRENTLY_ON(UI); here, too?

[Shuhei Takahashi, 2016/07/26 05:41:43]

This function was removed.

+    ImageDecoder::Cancel(inflight_request_.get());
+    inflight_request_.reset();
+  }
+}
+
 }  // namespace arc