BufferQueue: clean up buffer counting

This change is a clean up of some of the handling of the maximum number of
buffers that are allowed at once.  It mostly renames a few member variables and
methods, but it includes a couple small refactorings.

Change-Id: I9959310f563d09583548d4291e1050a7bbc7d87d
diff --git a/include/gui/SurfaceTexture.h b/include/gui/SurfaceTexture.h
index 98741c5..2570cd9 100644
--- a/include/gui/SurfaceTexture.h
+++ b/include/gui/SurfaceTexture.h
@@ -87,10 +87,10 @@
     // when finished with it.
     void setReleaseFence(int fenceFd);
 
-    // setBufferCountServer set the buffer count. If the client has requested
-    // a buffer count using setBufferCount, the server-buffer count will
-    // take effect once the client sets the count back to zero.
-    status_t setBufferCountServer(int bufferCount);
+    // setDefaultMaxBufferCount sets the default limit on the maximum number
+    // of buffers that will be allocated at one time. The image producer may
+    // override the limit.
+    status_t setDefaultMaxBufferCount(int bufferCount);
 
     // getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
     // associated with the texture image set by the most recent call to