zero-copy: Clarify to allocate/destroy GpuMemoryBuffer on any thread and use it on the main thread o

ui/ozone/platform/test/test_window_manager.cc

Index: ui/ozone/platform/test/test_window_manager.cc
diff --git a/ui/ozone/platform/test/test_window_manager.cc b/ui/ozone/platform/test/test_window_manager.cc
index 3ff3a471dde45693f2cb7da0fdadec7928f1bccc..cd48bf33eefdacdd347c4280c64bf5e31fc14aa3 100644
--- a/ui/ozone/platform/test/test_window_manager.cc
+++ b/ui/ozone/platform/test/test_window_manager.cc
@@ -69,6 +69,7 @@ TestWindowManager::TestWindowManager(const base::FilePath& dump_location)
 }
 
 TestWindowManager::~TestWindowManager() {
+  DCHECK(thread_checker_.CalledOnValidThread());
 }
 
 void TestWindowManager::Initialize() {
@@ -96,6 +97,7 @@ base::FilePath TestWindowManager::base_path() const {
 
 scoped_ptr<SurfaceOzoneCanvas> TestWindowManager::CreateCanvasForWidget(
     gfx::AcceleratedWidget widget) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   TestWindow* window = windows_.Lookup(widget);
   DCHECK(window);
   return make_scoped_ptr<SurfaceOzoneCanvas>(new FileSurface(window->path()));
@@ -104,6 +106,7 @@ scoped_ptr<SurfaceOzoneCanvas> TestWindowManager::CreateCanvasForWidget(
 bool TestWindowManager::LoadEGLGLES2Bindings(
     AddGLLibraryCallback add_gl_library,
     SetGLGetProcAddressProcCallback set_gl_get_proc_address) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   return false;
 }