Revert 258122 "gpu: Allow fences to check whether a flush has oc..."

trunk/src/gpu/command_buffer/service/texture_definition.cc

Index: trunk/src/gpu/command_buffer/service/texture_definition.cc
===================================================================
--- trunk/src/gpu/command_buffer/service/texture_definition.cc	(revision 258964)
+++ trunk/src/gpu/command_buffer/service/texture_definition.cc	(working copy)
@@ -278,8 +278,12 @@
 
 void NativeImageBuffer::DidWrite(gfx::GLImage* client) {
   base::AutoLock lock(lock_);
-  // Sharing semantics require the client to flush in order to make changes
-  // visible to other clients.
+  // TODO(sievers): crbug.com/352419
+  // This is super-risky. We need to somehow find out about when the current
+  // context gets flushed, so that we will only ever wait on the write fence
+  // (esp. from another context) if it was flushed and is guaranteed to clear.
+  // On the other hand, proactively flushing here is not feasible in terms
+  // of perf when there are multiple draw calls per frame.
   write_fence_.reset(gfx::GLFence::CreateWithoutFlush());
   write_client_ = client;
   for (std::list<ClientInfo>::iterator it = client_infos_.begin();