Unifying the various texture interfaces where possible

Also fixed diamond inheritance pattern that was causing trouble
on Windows 8

BUG=angle:688, angle:720
Change-Id: I678826bd4f3927c68ca1eb2e018dbb5aad33a8cc
Reviewed-on: https://chromium-review.googlesource.com/211037
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Brandon Jones <bajones@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libGLESv2/FramebufferAttachment.cpp b/src/libGLESv2/FramebufferAttachment.cpp
index e7855b1..6f40edf 100644
--- a/src/libGLESv2/FramebufferAttachment.cpp
+++ b/src/libGLESv2/FramebufferAttachment.cpp
@@ -95,7 +95,7 @@
 
 rx::RenderTarget *Texture2DAttachment::getDepthStencil()
 {
-    return mTexture2D->getDepthSencil(mLevel);
+    return mTexture2D->getDepthStencil(mLevel);
 }
 
 rx::TextureStorage *Texture2DAttachment::getTextureStorage()