Make WindowReachedScreen support async readback

ui/snapshot/snapshot_android.cc

Index: ui/snapshot/snapshot_android.cc
diff --git a/ui/snapshot/snapshot_android.cc b/ui/snapshot/snapshot_android.cc
index 01895539e557ae706ce2cfd48ae8878b2267d826..837c13c8d4f1578446fa1b1a1c0529f629868e7a 100644
--- a/ui/snapshot/snapshot_android.cc
+++ b/ui/snapshot/snapshot_android.cc
@@ -8,6 +8,7 @@
 #include "ui/base/android/view_android.h"
 #include "ui/base/android/window_android.h"
 #include "ui/gfx/display.h"
+#include "ui/gfx/image/image.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/screen.h"
 
@@ -39,7 +40,15 @@ void GrabWindowSnapshotAndScaleAsync(
     const gfx::Size& target_size,
     scoped_refptr<base::TaskRunner> background_task_runner,
     GrabWindowSnapshotAsyncCallback callback) {
-  NOTIMPLEMENTED();
+  callback.Run(gfx::Image());
+}
+
+void GrabViewSnapshotAsync(
+    gfx::NativeView view,
+    const gfx::Rect& source_rect,
+    scoped_refptr<base::TaskRunner> background_task_runner,
+    const GrabWindowSnapshotAsyncPNGCallback& callback) {
+  callback.Run(scoped_refptr<base::RefCountedBytes>());
 }
 
 void GrabWindowSnapshotAsync(
@@ -47,7 +56,7 @@ void GrabWindowSnapshotAsync(
     const gfx::Rect& source_rect,
     scoped_refptr<base::TaskRunner> background_task_runner,
     const GrabWindowSnapshotAsyncPNGCallback& callback) {
-  NOTIMPLEMENTED();
+  callback.Run(scoped_refptr<base::RefCountedBytes>());
 }
 
 }  // namespace ui