Enable async upload egl with mailbox synchronizer

With the workaround in r286800, mailbox synchronizer skips tile
textures, so is compatible with async transfer egl.

This is a partial revert of r286501.

BUG=399311

Review URL: https://codereview.chromium.org/463563002

Cr-Commit-Position: refs/heads/master@{#289172}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289172 0039d316-1c4b-4281-b951-d872f2087c98

gpu/command_buffer/service/async_pixel_transfer_manager_android.cc

@@ -10,7 +10,6 @@
 #include "gpu/command_buffer/service/async_pixel_transfer_manager_idle.h"
 #include "gpu/command_buffer/service/async_pixel_transfer_manager_stub.h"
 #include "gpu/command_buffer/service/async_pixel_transfer_manager_sync.h"
-#include "gpu/command_buffer/service/mailbox_synchronizer.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_implementation.h"
 
@@ -64,8 +63,7 @@ AsyncPixelTransferManager* AsyncPixelTransferManager::Create(
           !IsBroadcom() &&
           !IsImagination() &&
           !IsNvidia31() &&
-          !base::SysInfo::IsLowEndDevice() &&
-          !gles2::MailboxSynchronizer::GetInstance()) {
+          !base::SysInfo::IsLowEndDevice()) {
         return new AsyncPixelTransferManagerEGL;
       }
       return new AsyncPixelTransferManagerIdle;