cheets: implement cros side of WallpaperManagerService.

chrome/browser/chromeos/arc/arc_wallpaper_handler.cc

Index: chrome/browser/chromeos/arc/arc_wallpaper_handler.cc
diff --git a/chrome/browser/chromeos/arc/arc_wallpaper_handler.cc b/chrome/browser/chromeos/arc/arc_wallpaper_handler.cc
index 238a9837e121ffe019e3e1076c9429b7ff177420..9039d506f1f9d1fe7eeafdb98a2d17154093b7a0 100644
--- a/chrome/browser/chromeos/arc/arc_wallpaper_handler.cc
+++ b/chrome/browser/chromeos/arc/arc_wallpaper_handler.cc
@@ -8,6 +8,9 @@
 #include <utility>
 #include <vector>
 
+#include "ash/desktop_background/desktop_background_controller.h"
+#include "ash/shell.h"
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.h"
@@ -16,7 +19,9 @@
 #include "components/wallpaper/wallpaper_files_id.h"
 #include "components/wallpaper/wallpaper_layout.h"
 #include "content/public/browser/browser_thread.h"
+#include "ui/gfx/image/image.h"
 #include "ui/gfx/image/image_skia.h"
+#include "ui/gfx/image/image_util.h"
 
 using user_manager::UserManager;
 
@@ -56,6 +61,17 @@ void SetBitmapAsWallpaper(const SkBitmap& bitmap) {
   // wallpaper_private_api.cc.
 }
 
+void EncodeImageJPEG(const gfx::Image image,
+                     std::shared_ptr<std::vector<uint8_t>> result) {
+  gfx::JPEG1xEncodedDataFromImage(image, 100, result.get());
+}
+
+void OnImageEncoded(
+    std::shared_ptr<std::vector<uint8_t>> result,
+    const base::Callback<void(std::vector<uint8_t> image)>& callback) {
+  callback.Run(*result.get());
+}
+
 }  // namespace
 
 ArcWallpaperHandler::ArcWallpaperHandler() = default;
@@ -76,6 +92,18 @@ void ArcWallpaperHandler::SetWallpaper(std::vector<uint8_t> jpeg_data) {
                                  ImageDecoder::ROBUST_JPEG_CODEC, true);
 }
 
+void ArcWallpaperHandler::GetWallpaper(
+    const base::Callback<void(std::vector<uint8_t> image)>& callback) const {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  ash::DesktopBackgroundController* dbc =
+      ash::Shell::GetInstance()->desktop_background_controller();
+  gfx::Image wallpaper(dbc->GetWallpaper());
+  std::shared_ptr<std::vector<uint8_t>> buffer(new std::vector<uint8_t>());

[xiyuan, 2016/08/23 20:43:47]

I would avoid shared_ptr. Either use PostTaskAndReplyWithResult, or use
base::Owned() for |buffer|.

e.g.
  // Use PostTaskAndReplyWithResult
  // std::vector<uint8_t> EncodeImageJPEG(const gfx::Image image)...
  // void OnImageEncoded(
  //     const base::Callback<void(std::vector<uint8_t> image)>& callback,
  //     const std::vector<uint8_t>& bytes);
  base::PostTaskAndReplyWithResult(
      BrowserThread::GetBlockingPool(),
      FROM_HERE,
      base::Bind(&EncodeImageJPEG, wallpaper),
      base::Bind(&OnImageEncoded, callback));

  // Use base::Owned
  std::vector<uint8_t>* buffer = new std::vector<uint8_t>();
  content::BrowserThread::GetBlockingPool()->PostTaskAndReply(
      FROM_HERE,
      base::Bind(&EncodeImageJPEG, wallpaper, buffer),
      base::Bind(&OnImageEncoded, base::Owned(buffer), callback));

[Muyuan, 2016/08/23 21:20:38]

Thx

+  content::BrowserThread::GetBlockingPool()->PostTaskAndReply(
+      FROM_HERE, base::Bind(&EncodeImageJPEG, std::move(wallpaper), buffer),

[xiyuan, 2016/08/23 20:43:47]

nit: std::move is not necessary, gfx::Image assignment is cheap.

[Muyuan, 2016/08/23 21:20:38]

Done.

+      base::Bind(&OnImageEncoded, buffer, callback));
+}
+
 void ArcWallpaperHandler::OnImageDecoded(const SkBitmap& bitmap) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   SetBitmapAsWallpaper(bitmap);