Refactor the wallpaper encoding to another file/class.

chrome/browser/ui/webui/options2/chromeos/wallpaper_source.cc

Index: chrome/browser/ui/webui/options2/chromeos/wallpaper_source.cc
diff --git a/chrome/browser/ui/webui/options2/chromeos/wallpaper_source.cc b/chrome/browser/ui/webui/options2/chromeos/wallpaper_source.cc
index 70e1d09d04902aeb1abf6bf254e726514ca47d77..05323cb3f0ac0dfb10da2f57eaeb5be3a4f02cc5 100644
--- a/chrome/browser/ui/webui/options2/chromeos/wallpaper_source.cc
+++ b/chrome/browser/ui/webui/options2/chromeos/wallpaper_source.cc
@@ -7,92 +7,16 @@
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "ash/shell.h"
 #include "base/debug/trace_event.h"
-#include "base/synchronization/cancellation_flag.h"
-#include "base/threading/worker_pool.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
+#include "chrome/browser/ui/webui/options2/chromeos/simple_png_encoder.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/browser_thread.h"
 #include "grit/ui_resources.h"
 #include "net/base/mime_util.h"
-#include "ui/gfx/codec/png_codec.h"
-#include "ui/gfx/size.h"
-#include "ui/gfx/skia_util.h"
-
-extern "C" {
-#if defined(USE_SYSTEM_ZLIB)
-#include <zlib.h>
-#else
-#include "third_party/zlib/zlib.h"
-#endif
-}
 
 namespace chromeos {
 namespace options2 {
 
-// Operation class that encodes existing in-memory image as PNG.
-// It uses NO-COMPRESSION to save time.
-class WallpaperImageSource::WallpaperEncodingOperation
-    : public base::RefCountedThreadSafe<
-          WallpaperImageSource::WallpaperEncodingOperation> {
- public:
-  WallpaperEncodingOperation(
-      int request_id,
-      scoped_refptr<base::RefCountedBytes> data,
-      SkBitmap image)
-      : request_id_(request_id),
-        data_(data),
-        image_(image) {
-  }
-
-  static void Run(scoped_refptr<WallpaperEncodingOperation> weo) {
-    weo->EncodeWallpaper();
-  }
-
-  int request_id() {
-    return request_id_;
-  }
-
-  void EncodeWallpaper() {
-    if (cancel_flag_.IsSet())
-      return;
-    TRACE_EVENT0("LOCK_SCREEN", "imageEncoding");
-    SkAutoLockPixels lock_input(image_);
-    // Avoid compression to make things faster.
-    gfx::PNGCodec::EncodeWithCompressionLevel(
-        reinterpret_cast<unsigned char*>(image_.getAddr32(0, 0)),
-        gfx::PNGCodec::FORMAT_SkBitmap,
-        gfx::Size(image_.width(), image_.height()),
-        image_.width() * image_.bytesPerPixel(),
-        false,
-        std::vector<gfx::PNGCodec::Comment>(),
-        Z_NO_COMPRESSION,
-        &data_->data());
-    if (cancel_flag_.IsSet())
-      return;
-  }
-
-  void Cancel() {
-    cancel_flag_.Set();
-  }
-
- private:
-  friend class base::RefCountedThreadSafe<
-      WallpaperImageSource::WallpaperEncodingOperation>;
-
-  ~WallpaperEncodingOperation() {}
-
-  base::CancellationFlag cancel_flag_;
-
-  // ID of original request.
-  int request_id_;
-  // Buffer to store encoded image.
-  scoped_refptr<base::RefCountedBytes> data_;
-  // Original image to encode.
-  SkBitmap image_;
-
-  DISALLOW_COPY_AND_ASSIGN(WallpaperEncodingOperation);
-};
-
 WallpaperImageSource::WallpaperImageSource()
     : DataSource(chrome::kChromeUIWallpaperImageHost, NULL),
       weak_ptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
@@ -143,31 +67,37 @@ void WallpaperImageSource::ImageAcquired(SkBitmap image,
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
   CancelPendingEncodingOperation();
   scoped_refptr<base::RefCountedBytes> data = new base::RefCountedBytes();
-  wallpaper_encoding_op_ = new WallpaperEncodingOperation(request_id,
-                                                          data,
-                                                          image);
-  base::WorkerPool::PostTaskAndReply(
-      FROM_HERE,
-      base::Bind(&WallpaperEncodingOperation::Run, wallpaper_encoding_op_),
+
+  png_encoder_ = new SimplePngEncoder(
+      data,
+      image,
+      base::Bind(&WallpaperImageSource::CancelCallback,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 request_id));
+
+  TRACE_EVENT0("LOCK_SCREEN", "imageEncoding");
+  png_encoder_->Run(
       base::Bind(&WallpaperImageSource::SendCurrentUserWallpaper,
-                 weak_ptr_factory_.GetWeakPtr(), request_id, data),
-      true /* task_is_slow */);
+                 weak_ptr_factory_.GetWeakPtr(),
+                 request_id));
 };
 
 void WallpaperImageSource::CancelPendingEncodingOperation() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
   // Set canceled flag of previous request to skip unneeded encoding.
-  if (wallpaper_encoding_op_.get()) {
-    wallpaper_encoding_op_->Cancel();
-    SendResponse(wallpaper_encoding_op_->request_id(), NULL);
-    TRACE_EVENT_ASYNC_END0("SCREEN_LOCK", "GetUserWallpaper",
-                           wallpaper_encoding_op_->request_id());
+  if (png_encoder_.get()) {
+    png_encoder_->Cancel();
   }
 
-  // Cancel reply callback for previous request.
+  // Cancel the callback for the previous request.
   weak_ptr_factory_.InvalidateWeakPtrs();
 }
 
+void WallpaperImageSource::CancelCallback(int request_id) {
+    SendResponse(request_id, NULL);
+    TRACE_EVENT_ASYNC_END0("SCREEN_LOCK", "GetUserWallpaper", request_id);
+}
+
 void WallpaperImageSource::SendCurrentUserWallpaper(int request_id,
     scoped_refptr<base::RefCountedBytes> data) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));