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/libs/ui/Gralloc1.cpp b/libs/ui/Gralloc1.cpp
index 0083f58..7952ed6 100644
--- a/libs/ui/Gralloc1.cpp
+++ b/libs/ui/Gralloc1.cpp
@@ -17,6 +17,7 @@
 //#define LOG_NDEBUG 0
 
 #include <ui/Gralloc1.h>
+#include <ui/GraphicBuffer.h>
 
 #include <vector>