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/DisplayListOp.h b/libs/hwui/DisplayListOp.h
index d78c1cb..39f89e5 100644
--- a/libs/hwui/DisplayListOp.h
+++ b/libs/hwui/DisplayListOp.h
@@ -32,6 +32,9 @@
 #include "AssetAtlas.h"
 #include "DeferredDisplayList.h"
 #include "DisplayListRenderer.h"
+#include "GammaFontRenderer.h"
+#include "Patch.h"
+#include "RenderNode.h"
 #include "UvMapper.h"
 #include "utils/LinearAllocator.h"