SF: Introduce OutputLayerCompositionState

This moves the display-dependent state from LayerBE.h to a new
OutputLayerCompositionState.h header, adds some simple accessors to
get the new state, and minimally adjusts the existing SurfaceFlinger
code to use the new structure.

Test: atest libsurfaceflinger_unittest libcompositionengine_test
Bug: 121291683
Change-Id: I00370f05dc6b2a3db34094862c46084e7575dbda
diff --git a/services/surfaceflinger/RenderArea.h b/services/surfaceflinger/RenderArea.h
index 9bad6de..edc6442 100644
--- a/services/surfaceflinger/RenderArea.h
+++ b/services/surfaceflinger/RenderArea.h
@@ -7,6 +7,8 @@
 
 namespace android {
 
+class DisplayDevice;
+
 // RenderArea describes a rectangular area that layers can be rendered to.
 //
 // There is a logical render area and a physical render area.  When a layer is
@@ -76,6 +78,8 @@
     // covered by any rendered layer should be filled with this color.
     CaptureFill getCaptureFill() const { return mCaptureFill; };
 
+    virtual const sp<const DisplayDevice> getDisplayDevice() const = 0;
+
 private:
     const uint32_t mReqWidth;
     const uint32_t mReqHeight;