arc: IPC method to set custom wallpaper.

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 "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"
+
+namespace arc {
+
+namespace {
+
+const char kAndroidWallpaperFilename[] = "android.jpg";

[Yusuke Sato, 2016/06/15 16:45:01]

nit: constexpr seems to be the new preferred way.

[Shuhei Takahashi, 2016/06/15 18:14:37]

Done.

+
+}  // namespace
+
+void ArcWallpaperHandler::SetWallpaper(const gfx::ImageSkia& image) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  chromeos::WallpaperManager* wallpaper_manager =
+      chromeos::WallpaperManager::Get();
+
+  const AccountId& account_id =
+      user_manager::UserManager::Get()->GetPrimaryUser()->GetAccountId();
+  wallpaper::WallpaperFilesId wallpaper_files_id =
+      wallpaper_manager->GetFilesId(account_id);
+  bool update_wallpaper =
+      account_id ==
+      user_manager::UserManager::Get()->GetActiveUser()->GetAccountId();
+  // TODO(crbug.com/618922): Allow specifying layout.
+  wallpaper_manager->SetCustomWallpaper(
+      account_id, wallpaper_files_id, kAndroidWallpaperFilename,
+      wallpaper::WALLPAPER_LAYOUT_STRETCH, user_manager::User::CUSTOMIZED,
+      image, update_wallpaper);
+
+  // 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 refactor thumbnail generation logic in
+  // wallpaper_api.cc and wallpaper_private_api.cc into WallpaperManager, but
+  // it might be quite a lot of work.

[xdai1, 2016/06/15 16:30:14]

That won't work. What you need to do is save the wallpaper and the thumbnail to
the Wallpaper Picker's sandboxed filesystem. The way to do that basically looks
like:
https://cs.chromium.org/chromium/src/chrome/browser/chromeos/extensions/wallp...

and
https://cs.chromium.org/chromium/src/chrome/browser/resources/chromeos/wallpa...

[Shuhei Takahashi, 2016/06/15 18:14:37]

Thanks, updated the comment accordingly.

+}
+
+}  // namespace arc