Free worker context resources on idle.

gpu/command_buffer/client/context_support.h

Index: gpu/command_buffer/client/context_support.h
diff --git a/gpu/command_buffer/client/context_support.h b/gpu/command_buffer/client/context_support.h
index 543025d81045b94737446e3bd0c8b457a511f2f1..e138ce0e85dfd9e0edd9e541b3955a94e513aa80 100644
--- a/gpu/command_buffer/client/context_support.h
+++ b/gpu/command_buffer/client/context_support.h
@@ -59,6 +59,13 @@ class ContextSupport {
       std::unique_ptr<ScopedVisibility> visibility) = 0;
   virtual bool AnyClientsVisible() const = 0;
 
+  class ScopedBusy {};
+  virtual std::unique_ptr<ScopedBusy> ClientBecameBusy() = 0;
+  virtual void ClientBecameNotBusy(std::unique_ptr<ScopedBusy> busy) = 0;
+
+  // A callback which will be invoked when the context is considered idle.
+  virtual void SetIdleCallback(const base::Closure& callback) = 0;
+
  protected:
   ContextSupport() {}
   virtual ~ContextSupport() {}