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..b9e7879e79be30fe48be6e7e67df01b93a0913e1 100644
--- a/chrome/browser/chromeos/arc/arc_wallpaper_handler.cc
+++ b/chrome/browser/chromeos/arc/arc_wallpaper_handler.cc
@@ -8,15 +8,21 @@
 #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 "base/task_runner_util.h"
 #include "chrome/browser/chromeos/login/users/wallpaper/wallpaper_manager.h"
 #include "components/signin/core/account_id/account_id.h"
 #include "components/user_manager/user_manager.h"
 #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 +62,12 @@ void SetBitmapAsWallpaper(const SkBitmap& bitmap) {
   // wallpaper_private_api.cc.
 }
 
+std::vector<uint8_t> EncodeImageJPEG(const gfx::Image image) {

[hidehiko, 2016/08/24 16:22:18]

const ref to avoid the copy?

+  std::vector<uint8_t> result;
+  gfx::JPEG1xEncodedDataFromImage(image, 100, &result);
+  return result;
+}
+
 }  // namespace
 
 ArcWallpaperHandler::ArcWallpaperHandler() = default;
@@ -76,6 +88,17 @@ 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());
+  base::PostTaskAndReplyWithResult(
+      content::BrowserThread::GetBlockingPool(), FROM_HERE,
+      base::Bind(&EncodeImageJPEG, wallpaper), callback);

[hidehiko, 2016/08/24 16:22:18]

std::move is needed to avoid the copy?

[xiyuan, 2016/08/24 17:16:29]

gfx::Image is cheap to copy since it only increment the storage's ref count. [1]
IMHO, std::move does not make a real difference.

[1]: https://cs.chromium.org/chromium/src/ui/gfx/image/image.h?rcl=0&l=82-86

+}
+
 void ArcWallpaperHandler::OnImageDecoded(const SkBitmap& bitmap) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   SetBitmapAsWallpaper(bitmap);