[Remoting Android] Fix thread issue with OpenGL drawable

remoting/client/display/gl_cursor.cc

Index: remoting/client/display/gl_cursor.cc
diff --git a/remoting/client/display/gl_cursor.cc b/remoting/client/display/gl_cursor.cc
index 113de2566533260551eaa8a19fdf55053f091cd8..07f7a014ecea3fee512156e2926f42ca6bb3f03f 100644
--- a/remoting/client/display/gl_cursor.cc
+++ b/remoting/client/display/gl_cursor.cc
@@ -18,7 +18,9 @@ namespace {
 const int kDefaultCursorDataSize = 32 * 32 * GlRenderLayer::kBytesPerPixel;
 }  // namespace
 
-GlCursor::GlCursor() : weak_factory_(this) {}
+GlCursor::GlCursor() : weak_factory_(this) {
+  weak_ptr_ = weak_factory_.GetWeakPtr();

[Sergey Ulanov, 2017/01/13 02:03:10]

With the current implementation of WeakFactory to make GetWeakPtr() safe you
just need to call GetWeakPtr() here, but don't need to keep the result. But see
my next comment.

+}
 
 GlCursor::~GlCursor() {}
 
@@ -81,7 +83,6 @@ void GlCursor::SetCanvas(base::WeakPtr<Canvas> canvas) {
 }
 
 bool GlCursor::Draw() {
-  DCHECK(thread_checker_.CalledOnValidThread());
   if (layer_ && current_cursor_data_ && visible_) {
     layer_->Draw(1.f);
   }
@@ -105,8 +106,7 @@ void GlCursor::SetCurrentCursorShape(bool size_changed) {
 }
 
 base::WeakPtr<Drawable> GlCursor::GetWeakPtr() {

[Sergey Ulanov, 2017/01/13 02:03:10]

Does this function really need to be thread-safe? The renderer overall should be
single-threaded, so I don't see any case when it can be useful to call this
function on any thread other than the one where it's created.

[nicholss, 2017/01/13 16:45:00]

I think in the future it will be accessed via many threads potentially. 

-  DCHECK(thread_checker_.CalledOnValidThread());
-  return weak_factory_.GetWeakPtr();
+  return weak_ptr_;
 }
 
 }  // namespace remoting