Revert "[SurfaceFlinger] Add GPU protected content support."

This reverts commit dc979249d3bdd678e63358aacb27aa9a5cd02f51.

Reason for revert: broke emulator b/121038163

Change-Id: I3c93fe7d91431a3000094915c909811d1796305d
diff --git a/services/surfaceflinger/BufferLayer.h b/services/surfaceflinger/BufferLayer.h
index be16cf5..690a4e5 100644
--- a/services/surfaceflinger/BufferLayer.h
+++ b/services/surfaceflinger/BufferLayer.h
@@ -71,10 +71,6 @@
     // isVisible - true if this layer is visible, false otherwise
     bool isVisible() const override;
 
-    // isProtected - true if the layer may contain protected content in the
-    // GRALLOC_USAGE_PROTECTED sense.
-    bool isProtected() const override;
-
     // isFixedSize - true if content has a fixed size
     bool isFixedSize() const override;
 
@@ -153,6 +149,13 @@
 
     virtual void setHwcLayerBuffer(DisplayId displayId) = 0;
 
+    // -----------------------------------------------------------------------
+
+public:
+    // isProtected - true if the layer may contain protected content in the
+    // GRALLOC_USAGE_PROTECTED sense.
+    bool isProtected() const;
+
 protected:
     // Loads the corresponding system property once per process
     static bool latchUnsignaledBuffers();