Add BufferHub-based IGBC implementation

This is mostly a placeholder to create an IGBC/IGBP pair based on
BufferHub for testing purpose. A fully functional implementation will be
filled in later.

Bug: 72972441
Bug: 70046255
Test: libgui_test
Change-Id: I2215bd78da1d0104f2cbb9599f874c810898be56
diff --git a/libs/gui/Android.bp b/libs/gui/Android.bp
index 6655eb6..a1a0928 100644
--- a/libs/gui/Android.bp
+++ b/libs/gui/Android.bp
@@ -85,6 +85,7 @@
 
     srcs: [
         "BitTube.cpp",
+        "BufferHubConsumer.cpp",
         "BufferHubProducer.cpp",
         "BufferItem.cpp",
         "BufferItemConsumer.cpp",