Add the SurfaceTexture C++ implementation.

This change adds the C++ implementation of SurfaceTexture and related
classes. The goal of this is for a SurfaceTexture to be passed to
camera service or Stagefright in place of a Surface to allow camera
preview or decoded video frames to be streamed to an OpenGL ES texture
that an application can use.

Change-Id: I55c83a7017f1ecb81c9c9e3252cbd118b914296c
diff --git a/include/ui/GraphicBuffer.h b/include/ui/GraphicBuffer.h
index aa65d93..8b256f4 100644
--- a/include/ui/GraphicBuffer.h
+++ b/include/ui/GraphicBuffer.h
@@ -121,6 +121,7 @@
     friend class Surface;
     friend class BpSurface;
     friend class BnSurface;
+    friend class SurfaceTextureClient;
     friend class LightRefBase<GraphicBuffer>;
     GraphicBuffer(const GraphicBuffer& rhs);
     GraphicBuffer& operator = (const GraphicBuffer& rhs);