Introduce the image_decoder service

chrome/browser/image_decoder.cc

Index: chrome/browser/image_decoder.cc
diff --git a/chrome/browser/image_decoder.cc b/chrome/browser/image_decoder.cc
index 3815f26dc922621713773dbb4ee634ea70e37626..93360b7007c11ba8359abb1cd4186281aa08bcd8 100644
--- a/chrome/browser/image_decoder.cc
+++ b/chrome/browser/image_decoder.cc
@@ -7,53 +7,78 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/callback.h"
+#include "base/lazy_instance.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
-#include "chrome/browser/browser_process.h"
-#include "chrome/common/image_decoder.mojom.h"
-#include "chrome/grit/generated_resources.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/browser/utility_process_host.h"
-#include "services/service_manager/public/cpp/interface_provider.h"
+#include "content/public/common/service_manager_connection.h"
+#include "ipc/ipc_channel.h"
+#include "services/image_decoder/public/cpp/decode.h"
+#include "services/service_manager/public/cpp/connector.h"
 #include "third_party/skia/include/core/SkBitmap.h"
-#include "ui/base/l10n/l10n_util.h"
-
-using content::BrowserThread;
-using content::UtilityProcessHost;
 
 namespace {
 
 // static, Leaky to allow access from any thread.
 base::LazyInstance<ImageDecoder>::Leaky g_decoder = LAZY_INSTANCE_INITIALIZER;
 
-// How long to wait after the last request has been received before ending
-// batch mode.
-const int kBatchModeTimeoutSeconds = 5;
+const int64_t kMaxImageSizeInBytes =
+    static_cast<int64_t>(IPC::Channel::kMaximumMessageSize);
 
+// Note that this is always called on the thread which initiated the
+// corresponding image_decoder::Decode request.
 void OnDecodeImageDone(
     base::Callback<void(int)> fail_callback,
     base::Callback<void(const SkBitmap&, int)> success_callback,
     int request_id,
     const SkBitmap& image) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (!image.isNull() && !image.empty())
     success_callback.Run(image, request_id);
   else
     fail_callback.Run(request_id);
 }
 
-}  // namespace
+void BindToBrowserConnector(service_manager::mojom::ConnectorRequest request) {
+  if (!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI)) {
+    content::BrowserThread::PostTask(
+        content::BrowserThread::UI, FROM_HERE,
+        base::Bind(&BindToBrowserConnector, base::Passed(&request)));
+    return;
+  }
+
+  content::ServiceManagerConnection::GetForProcess()->GetConnector()
+      ->BindRequest(std::move(request));
+}
 
-ImageDecoder::ImageDecoder()
-    : image_request_id_counter_(0) {
-  // A single ImageDecoder instance should live for the life of the program.
-  // Explicitly add a reference so the object isn't deleted.
-  AddRef();
+void RunDecodeCallbackOnTaskRunner(
+    const image_decoder::mojom::ImageDecoder::DecodeImageCallback& callback,
+    scoped_refptr<base::SequencedTaskRunner> task_runner,
+    const SkBitmap& image) {
+  task_runner->PostTask(FROM_HERE, base::Bind(callback, image));
 }
 
-ImageDecoder::~ImageDecoder() {
+void DecodeImage(
+    std::vector<uint8_t> image_data,
+    image_decoder::mojom::ImageCodec codec,
+    bool shrink_to_fit,
+    const image_decoder::mojom::ImageDecoder::DecodeImageCallback& callback,
+    scoped_refptr<base::SequencedTaskRunner> callback_task_runner) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+
+  service_manager::mojom::ConnectorRequest connector_request;
+  std::unique_ptr<service_manager::Connector> connector =
+      service_manager::Connector::Create(&connector_request);
+  BindToBrowserConnector(std::move(connector_request));
+
+  image_decoder::Decode(connector.get(), image_data, codec, shrink_to_fit,
+                        kMaxImageSizeInBytes,
+                        base::Bind(&RunDecodeCallbackOnTaskRunner,
+                                   callback, callback_task_runner));
 }
 
+}  // namespace
+
 ImageDecoder::ImageRequest::ImageRequest()
     : task_runner_(base::ThreadTaskRunnerHandle::Get()) {
   DCHECK(sequence_checker_.CalledOnValidSequence());
@@ -70,6 +95,10 @@ ImageDecoder::ImageRequest::~ImageRequest() {
   ImageDecoder::Cancel(this);
 }
 
+ImageDecoder::ImageDecoder() : image_request_id_counter_(0) {}
+
+ImageDecoder::~ImageDecoder() {}
+
 // static
 void ImageDecoder::Start(ImageRequest* image_request,
                          std::vector<uint8_t> image_data) {
@@ -88,9 +117,8 @@ void ImageDecoder::StartWithOptions(ImageRequest* image_request,
                                     std::vector<uint8_t> image_data,
                                     ImageCodec image_codec,
                                     bool shrink_to_fit) {
-  g_decoder.Pointer()->StartWithOptionsImpl(image_request,
-                                            std::move(image_data),
-                                            image_codec, shrink_to_fit);
+  g_decoder.Get().StartWithOptionsImpl(image_request, std::move(image_data),
+                                       image_codec, shrink_to_fit);
 }
 
 // static
@@ -117,68 +145,35 @@ void ImageDecoder::StartWithOptionsImpl(ImageRequest* image_request,
     image_request_id_map_.insert(std::make_pair(request_id, image_request));
   }
 
-  BrowserThread::PostTask(
-      BrowserThread::IO, FROM_HERE,
-      base::Bind(
-          &ImageDecoder::DecodeImageInSandbox,
-          g_decoder.Pointer(), request_id,
-          base::Passed(std::move(image_data)),
-          image_codec, shrink_to_fit));
+  image_decoder::mojom::ImageCodec codec =
+      image_decoder::mojom::ImageCodec::DEFAULT;
+#if defined(OS_CHROMEOS)
+  if (image_codec == ROBUST_JPEG_CODEC)
+    codec = image_decoder::mojom::ImageCodec::ROBUST_JPEG;
+  if (image_codec == ROBUST_PNG_CODEC)
+    codec = image_decoder::mojom::ImageCodec::ROBUST_PNG;
+#endif  // defined(OS_CHROMEOS)
+
+  auto callback = base::Bind(
+      &OnDecodeImageDone,
+      base::Bind(&ImageDecoder::OnDecodeImageFailed, base::Unretained(this)),
+      base::Bind(&ImageDecoder::OnDecodeImageSucceeded, base::Unretained(this)),
+      request_id);
+
+  // NOTE: There exist ImageDecoder consumers which implicitly rely on this
+  // operation happening on a thread which always has a ThreadTaskRunnerHandle.
+  // We arbitrarily use the IO thread here to match details of the legacy
+  // implementation.
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO, FROM_HERE,
+      base::Bind(&DecodeImage, base::Passed(&image_data), codec, shrink_to_fit,
+                 callback, make_scoped_refptr(image_request->task_runner())));
 }
 
 // static
 void ImageDecoder::Cancel(ImageRequest* image_request) {
   DCHECK(image_request);
-  g_decoder.Pointer()->CancelImpl(image_request);
-}
-
-void ImageDecoder::DecodeImageInSandbox(
-    int request_id,
-    std::vector<uint8_t> image_data,
-    ImageCodec image_codec,
-    bool shrink_to_fit) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::AutoLock lock(map_lock_);
-  const auto it = image_request_id_map_.find(request_id);
-  if (it == image_request_id_map_.end())
-    return;
-
-  ImageRequest* image_request = it->second;
-  if (!utility_process_host_) {
-    StartBatchMode();
-  }
-  if (!utility_process_host_) {
-    // Utility process failed to start; notify delegate and return.
-    // Without this check, we were seeing crashes on startup. Further
-    // investigation is needed to determine why the utility process
-    // is failing to start. See crbug.com/472272
-    image_request->task_runner()->PostTask(
-        FROM_HERE,
-        base::Bind(&ImageDecoder::RunOnDecodeImageFailed, this, request_id));
-    return;
-  }
-
-  if (!batch_mode_timer_) {
-    // Created here so it will call StopBatchMode() on the right thread.
-    batch_mode_timer_.reset(new base::DelayTimer(
-        FROM_HERE, base::TimeDelta::FromSeconds(kBatchModeTimeoutSeconds), this,
-        &ImageDecoder::StopBatchMode));
-  }
-  batch_mode_timer_->Reset();
-
-  mojom::ImageCodec mojo_codec = mojom::ImageCodec::DEFAULT;
-#if defined(OS_CHROMEOS)
-  if (image_codec == ROBUST_JPEG_CODEC)
-    mojo_codec = mojom::ImageCodec::ROBUST_JPEG;
-  if (image_codec == ROBUST_PNG_CODEC)
-    mojo_codec = mojom::ImageCodec::ROBUST_PNG;
-#endif  // defined(OS_CHROMEOS)
-  decoder_->DecodeImage(
-      image_data, mojo_codec, shrink_to_fit,
-      base::Bind(&OnDecodeImageDone,
-                 base::Bind(&ImageDecoder::OnDecodeImageFailed, this),
-                 base::Bind(&ImageDecoder::OnDecodeImageSucceeded, this),
-                 request_id));
+  g_decoder.Get().CancelImpl(image_request);
 }
 
 void ImageDecoder::CancelImpl(ImageRequest* image_request) {
@@ -193,104 +188,9 @@ void ImageDecoder::CancelImpl(ImageRequest* image_request) {
   }
 }
 
-void ImageDecoder::StartBatchMode() {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  utility_process_host_ =
-      UtilityProcessHost::Create(
-          this, base::ThreadTaskRunnerHandle::Get().get())->AsWeakPtr();
-  utility_process_host_->SetName(l10n_util::GetStringUTF16(
-      IDS_UTILITY_PROCESS_IMAGE_DECODER_NAME));
-  if (!utility_process_host_->Start()) {
-    delete utility_process_host_.get();
-    return;
-  }
-  utility_process_host_->GetRemoteInterfaces()->GetInterface(&decoder_);
-}
-
-void ImageDecoder::StopBatchMode() {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  {
-    // Check for outstanding requests and wait for them to finish.
-    base::AutoLock lock(map_lock_);
-    if (!image_request_id_map_.empty()) {
-      batch_mode_timer_->Reset();
-      return;
-    }
-  }
-
-  if (utility_process_host_) {
-    // With Mojo, the utility process needs to be explicitly shut down by
-    // deleting the host.
-    delete utility_process_host_.get();
-    decoder_.reset();
-    utility_process_host_.reset();
-  }
-}
-
-void ImageDecoder::FailAllRequests() {
-  RequestMap requests;
-  {
-    base::AutoLock lock(map_lock_);
-    requests = image_request_id_map_;
-  }
-
-  // Since |OnProcessCrashed| and |OnProcessLaunchFailed| are run asynchronously
-  // from the actual event, it's possible for a new utility process to have been
-  // created and sent requests by the time these functions are run. This results
-  // in failing requests that are unaffected by the crash. Although not ideal,
-  // this is valid and simpler than tracking which request is sent to which
-  // utility process, and whether the request has been sent at all.
-  for (const auto& request : requests)
-    OnDecodeImageFailed(request.first);
-}
-
-void ImageDecoder::OnProcessCrashed(int exit_code) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  FailAllRequests();
-}
-
-void ImageDecoder::OnProcessLaunchFailed(int error_code) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  FailAllRequests();
-}
-
-bool ImageDecoder::OnMessageReceived(const IPC::Message& message) {
-  return false;
-}
-
 void ImageDecoder::OnDecodeImageSucceeded(
     const SkBitmap& decoded_image,
     int request_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::AutoLock lock(map_lock_);
-  auto it = image_request_id_map_.find(request_id);
-  if (it == image_request_id_map_.end())
-    return;
-
-  ImageRequest* image_request = it->second;
-  image_request->task_runner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ImageDecoder::RunOnImageDecoded,
-                 this,
-                 decoded_image,
-                 request_id));
-}
-
-void ImageDecoder::OnDecodeImageFailed(int request_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  base::AutoLock lock(map_lock_);
-  auto it = image_request_id_map_.find(request_id);
-  if (it == image_request_id_map_.end())
-    return;
-
-  ImageRequest* image_request = it->second;
-  image_request->task_runner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ImageDecoder::RunOnDecodeImageFailed, this, request_id));
-}
-
-void ImageDecoder::RunOnImageDecoded(const SkBitmap& decoded_image,
-                                     int request_id) {
   ImageRequest* image_request;
   {
     base::AutoLock lock(map_lock_);
@@ -305,7 +205,7 @@ void ImageDecoder::RunOnImageDecoded(const SkBitmap& decoded_image,
   image_request->OnImageDecoded(decoded_image);
 }
 
-void ImageDecoder::RunOnDecodeImageFailed(int request_id) {
+void ImageDecoder::OnDecodeImageFailed(int request_id) {
   ImageRequest* image_request;
   {
     base::AutoLock lock(map_lock_);