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/AssetAtlas.h b/libs/hwui/AssetAtlas.h
index 2ec556e..6f72793 100644
--- a/libs/hwui/AssetAtlas.h
+++ b/libs/hwui/AssetAtlas.h
@@ -27,7 +27,6 @@
 
 #include <SkBitmap.h>
 
-#include "Image.h"
 #include "Texture.h"
 #include "UvMapper.h"
 
@@ -35,6 +34,7 @@
 namespace uirenderer {
 
 class Caches;
+class Image;
 
 /**
  * An asset atlas holds a collection of framework bitmaps in a single OpenGL