Add support for physically rotated displays

This feature is currently controled by a system property.
"ro.sf.hwrotation" can be set to either 90 or 270. It'll cause
SF to rotate the screen by 90 and 270 degres respectively.

That is, if the driver reports 800x480 for instance, and
ro.sf.hwrotation is set to 90, applications will "see" a
480x800 display and will run in portrait.

This is implemented by introducing an extra "display"
transformation in the GraphicPlane.
diff --git a/libs/surfaceflinger/SurfaceFlinger.h b/libs/surfaceflinger/SurfaceFlinger.h
index c0ab73d..2b7820c 100644
--- a/libs/surfaceflinger/SurfaceFlinger.h
+++ b/libs/surfaceflinger/SurfaceFlinger.h
@@ -116,9 +116,10 @@
         bool                    initialized() const;
 
         void                    setDisplayHardware(DisplayHardware *);
-        void                    setTransform(const Transform& tr);
         status_t                setOrientation(int orientation);
         int                     getOrientation() const { return mOrientation; }
+        int                     getWidth() const;
+        int                     getHeight() const;
 
         const DisplayHardware&  displayHardware() const;
         const Transform&        transform() const;
@@ -129,10 +130,13 @@
         GraphicPlane            operator = (const GraphicPlane&);
 
         DisplayHardware*        mHw;
-        Transform               mTransform;
-        Transform               mOrientationTransform;
         Transform               mGlobalTransform;
+        Transform               mDisplayTransform;
         int                     mOrientation;
+        float                   mDisplayWidth;
+        float                   mDisplayHeight;
+        int                     mWidth;
+        int                     mHeight;
 };
 
 // ---------------------------------------------------------------------------