Enable display rotation, magnifier in unified desktop mode

ash/host/transformer_helper.h

Index: ash/host/transformer_helper.h
diff --git a/ash/host/transformer_helper.h b/ash/host/transformer_helper.h
index d64af804d0d51e1f139370daa79cff3d206a20c4..0e24ad13977686d014b778923eebb77c49c7dee8 100644
--- a/ash/host/transformer_helper.h
+++ b/ash/host/transformer_helper.h
@@ -24,6 +24,9 @@ class TransformerHelper {
   explicit TransformerHelper(AshWindowTreeHost* ash_host);
   ~TransformerHelper();
 
+  // Initializes the transformer with identity transform.
+  void Init();
+
   // Returns the the insets that specifies the effective root window
   // area within the host window.
   gfx::Insets GetHostInsets() const;