Adds a function to Framebuffer to retrieve depth OR stencilbuffer.

src/libGLESv2/Framebuffer.cpp

@@ -202,6 +202,18 @@ Renderbuffer *Framebuffer::getStencilbuffer()
     return mStencilbufferPointer.get();
 }
 
+Renderbuffer *Framebuffer::getDepthOrStencilbuffer()
+{
+    Renderbuffer *depthstencilbuffer = mDepthbufferPointer.get();
+    
+    if (!depthstencilbuffer)
+    {
+        depthstencilbuffer = mStencilbufferPointer.get();
+    }
+
+    return depthstencilbuffer;
+}
+
 Renderbuffer *Framebuffer::getNullColorbuffer()
 {
     Renderbuffer *nullbuffer  = mNullColorbufferPointer.get();

src/libGLESv2/Framebuffer.h

@@ -54,6 +54,7 @@ class Framebuffer
     Renderbuffer *getColorbuffer();
     Renderbuffer *getDepthbuffer();
     Renderbuffer *getStencilbuffer();
+    Renderbuffer *getDepthOrStencilbuffer();
     Renderbuffer *getNullColorbuffer();
 
     GLenum getColorbufferType();