libgui: Add a BufferItem overload to IGBC::acquire

Adds an overload of IGraphicBufferConsumer::acquireBuffer which takes
an android::BufferItem instead of an IGBC::BufferItem.

Change-Id: I9c3bc8037fa9438d4d9080b8afb694219ef2f71f
diff --git a/include/gui/BufferQueueConsumer.h b/include/gui/BufferQueueConsumer.h
index 9c91fc7..92127c1 100644
--- a/include/gui/BufferQueueConsumer.h
+++ b/include/gui/BufferQueueConsumer.h
@@ -48,6 +48,8 @@
     // is CLOCK_MONOTONIC.
     virtual status_t acquireBuffer(BufferItem* outBuffer,
             nsecs_t expectedPresent);
+    virtual status_t acquireBuffer(android::BufferItem* outBuffer,
+            nsecs_t expectedPresent);
 
     // See IGraphicBufferConsumer::detachBuffer
     virtual status_t detachBuffer(int slot);