2 files changed, 27 insertions, 0 deletions
diff --git a/ui/surface/transport_dib.h b/ui/surface/transport_dib.h
index 3495c9d..70928ed 100644
--- a/ui/surface/transport_dib.h
+++ b/ui/surface/transport_dib.h
@@ -194,6 +194,15 @@ class SURFACE_EXPORT TransportDIB {
   // Map the shared memory into the X server and return an id for the shared
   // segment.
   XID MapToX(Display* connection);
+
+  void IncreaseInFlightCounter() { inflight_counter_++; }
+  // Decreases the inflight counter, and deletes the transport DIB if it is
+  // detached.
+  void DecreaseInFlightCounter();
+
+  // Deletes this transport DIB and detaches the shared memory once the
+  // |inflight_counter_| is zero.
+  void Detach();
 #endif
 
  private:
@@ -207,6 +216,8 @@ class SURFACE_EXPORT TransportDIB {
   void* address_;  // mapped address
   XSharedMemoryId x_shm_;  // X id for the shared segment
   Display* display_;  // connection to the X server
+  size_t inflight_counter_;  // How many requests to the X server are in flight
+  bool detached_;  // If true, delete the transport DIB when it is idle
 #endif
   size_t size_;  // length, in bytes
 
diff --git a/ui/surface/transport_dib_linux.cc b/ui/surface/transport_dib_linux.cc
index b1a5469..7763c0e 100644
--- a/ui/surface/transport_dib_linux.cc
+++ b/ui/surface/transport_dib_linux.cc
@@ -22,6 +22,8 @@ TransportDIB::TransportDIB()
     : address_(kInvalidAddress),
       x_shm_(0),
       display_(NULL),
+      inflight_counter_(0),
+      detached_(false),
       size_(0) {
 }
 
@@ -138,3 +140,17 @@ XID TransportDIB::MapToX(Display* display) {
 
   return x_shm_;
 }
+
+void TransportDIB::DecreaseInFlightCounter() {
+  CHECK(inflight_counter_);
+  inflight_counter_--;
+  if (!inflight_counter_ && detached_)
+    delete this;
+}
+
+void TransportDIB::Detach() {
+  CHECK(!detached_);
+  detached_ = true;
+  if (!inflight_counter_)
+    delete this;
+}