Makes BackgroundServiceLoader destroy loader on background thread

As the loader is used on the background thread it should also be
destroyed on the background thread. This way all usage is kept to a
single thread so that if the loader uses resources that require access
on the same thread we don't run into issues.

BUG=372585
TEST=covered by tests
R=davemoore@chromium.org

Review URL: https://codereview.chromium.org/276573013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270212 0039d316-1c4b-4281-b951-d872f2087c98

mojo/service_manager/background_service_loader.cc

@@ -91,6 +91,8 @@ void BackgroundServiceLoader::OnServiceErrorOnBackgroundThread(
 
 void BackgroundServiceLoader::ShutdownOnBackgroundThread() {
   delete background_loader_;
+  // Destroy |loader_| on the thread it's actually used on.
+  loader_.reset();
 }
 
 }  // namespace mojo

tools/valgrind/drmemory/suppressions.txt

@@ -512,41 +512,3 @@ NPCTRL.dll!DllGetClassObject
 NPCTRL.dll!DllGetClassObject
 NPCTRL.dll!DllGetClassObject
 NPCTRL.dll!DllGetClassObject
-
-GDI USAGE ERROR
-name=http://crbug.com/372512
-system call NtUserCallOneParam.RELEASEDC
-USER32.dll!ReleaseDC
-*!gfx::NativeViewGLSurfaceOSMesa::Destroy
-...
-*!mojo::services::CommandBufferImpl::~CommandBufferImpl
-...
-*!mojo::services::NativeViewportImpl::~NativeViewportImpl
-...
-*!mojo::Application::~Application
-...
-*!mojo::BackgroundServiceLoader::~BackgroundServiceLoader
-...
-*!mojo::ServiceManager::~ServiceManager
-*!mojo::shell::Context::~Context
-*!base::DeleteHelper<>::DoDelete
-
-HANDLE LEAK
-name=http://crbug.com/372585
-system call NtUserCreateWindowEx
-...
-USER32.dll!CreateWindowExW
-gfx.dll!gfx::WindowImpl::Init
-mojo_native_viewport_service.dll!mojo::services::NativeViewportWin::Init
-mojo_native_viewport_service.dll!mojo::services::NativeViewportImpl::Create
-mojo_native_viewport_service.dll!mojo::NativeViewportStub::Accept
-mojo_native_viewport_service.dll!mojo::internal::Router::HandleIncomingMessage
-mojo_native_viewport_service.dll!mojo::internal::MessageHeaderValidator::Accept
-mojo_native_viewport_service.dll!mojo::ReadAndDispatchMessage
-...
-base.dll!base::MessageLoop::RunTask
-base.dll!base::MessageLoop::DeferOrRunPendingTask
-base.dll!base::MessageLoop::DoWork
-base.dll!base::MessagePumpDefault::Run
-...
-base.dll!base::Thread::ThreadMain