Clean up physical coupling

Narrow the use of #include directives in hwui, replacing with forward
declarations where straightforward. Speeds compiles; doesn't do any
restructuring of code.

Change-Id: Icac2baffb5896f55d8c6718e9bd9d4bfa02d3ca0
diff --git a/libs/hwui/RenderState.h b/libs/hwui/RenderState.h
index cbe7cfc..107f9bb 100644
--- a/libs/hwui/RenderState.h
+++ b/libs/hwui/RenderState.h
@@ -20,15 +20,18 @@
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 #include <utils/Mutex.h>
+#include <utils/Functor.h>
 
 #include <private/hwui/DrawGlInfo.h>
 
-#include "Caches.h"
 #include "utils/Macros.h"
 
 namespace android {
 namespace uirenderer {
 
+class Caches;
+class Layer;
+
 namespace renderthread {
 class CanvasContext;
 class RenderThread;