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/libs/gui/SurfaceTexture.cpp b/libs/gui/SurfaceTexture.cpp
index c0b20df..9ed23be 100644
--- a/libs/gui/SurfaceTexture.cpp
+++ b/libs/gui/SurfaceTexture.cpp
@@ -125,9 +125,9 @@
     mBufferQueue->setConsumerUsageBits(DEFAULT_USAGE_FLAGS);
 }
 
-status_t SurfaceTexture::setBufferCountServer(int bufferCount) {
+status_t SurfaceTexture::setDefaultMaxBufferCount(int bufferCount) {
     Mutex::Autolock lock(mMutex);
-    return mBufferQueue->setBufferCountServer(bufferCount);
+    return mBufferQueue->setDefaultMaxBufferCount(bufferCount);
 }