BQ: add setMaxDequeuedBufferCount

Adds the new setMaxDequeuedBufferCount() function to
BufferQueueProducer. This will eventually replace setBufferCount.

Also add setAsyncMode.

Bug 13174928

Change-Id: Iea1adcd5d74a75f67d8e9dde06d521695628ad5a
diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
index 6298751..c315562 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
@@ -99,6 +99,8 @@
     //
     virtual status_t requestBuffer(int pslot, sp<GraphicBuffer>* outBuf);
     virtual status_t setBufferCount(int bufferCount);
+    virtual status_t setMaxDequeuedBufferCount(int maxDequeuedBuffers);
+    virtual status_t setAsyncMode(bool async);
     virtual status_t dequeueBuffer(int* pslot, sp<Fence>* fence, bool async,
             uint32_t w, uint32_t h, PixelFormat format, uint32_t usage);
     virtual status_t detachBuffer(int slot);