Break a dependency of libui on libandroid

This was only a header dependency, but it still
created a circular dependency, which will cause
problems in another CL.

We fix this by creating a libarect static library
containing only that header. both libui and
libandroid now depend on it and reexport the 
header. 

We also make sure rect.h ends-up in the right
place.

Test: built and booted device
Bug: 35164655

Change-Id: Iba25b8b801b26b26ec1401c00caf367a06f197ca
diff --git a/include/gui/BufferItemConsumer.h b/include/gui/BufferItemConsumer.h
index 56c7a3f..ec77ec7 100644
--- a/include/gui/BufferItemConsumer.h
+++ b/include/gui/BufferItemConsumer.h
@@ -18,18 +18,13 @@
 #define ANDROID_GUI_BUFFERITEMCONSUMER_H
 
 #include <gui/ConsumerBase.h>
-
-#include <ui/GraphicBuffer.h>
-
-#include <utils/String8.h>
-#include <utils/Vector.h>
-#include <utils/threads.h>
+#include <gui/BufferQueue.h>
 
 #define ANDROID_GRAPHICS_BUFFERITEMCONSUMER_JNI_ID "mBufferItemConsumer"
 
 namespace android {
 
-class BufferQueue;
+class String8;
 
 /**
  * BufferItemConsumer is a BufferQueue consumer endpoint that allows clients