diff --git a/include/private/surfaceflinger/SharedBufferStack.h b/include/private/surfaceflinger/SharedBufferStack.h
index d6ae5e9..9d589cf 100644
--- a/include/private/surfaceflinger/SharedBufferStack.h
+++ b/include/private/surfaceflinger/SharedBufferStack.h
@@ -285,6 +285,8 @@
     uint32_t getTransform(int buffer) const;
 
     status_t resize(int newNumBuffers);
+    status_t grow(int newNumBuffers);
+    status_t shrink(int newNumBuffers);
 
     SharedBufferStack::Statistics getStats() const;
     
@@ -346,6 +348,14 @@
     int mNumBuffers;
     BufferList mBufferList;
 
+    struct BuffersAvailableCondition : public ConditionBase {
+        int mNumBuffers;
+        inline BuffersAvailableCondition(SharedBufferServer* sbs,
+                int numBuffers);
+        inline bool operator()() const;
+        inline const char* name() const { return "BuffersAvailableCondition"; }
+    };
+
     struct UnlockUpdate : public UpdateBase {
         const int lockedBuffer;
         inline UnlockUpdate(SharedBufferBase* sbb, int lockedBuffer);