Remove non-const FBO attachment queries.

Methods that need to mutate the Framebuffer should use
setAttachment, etc, instead of using mutable pointers.

BUG=angleproject:963

Change-Id: Ibe7b8f8245f762916e0224fdc78796b1c933195f
Reviewed-on: https://chromium-review.googlesource.com/263490
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/Framebuffer.cpp b/src/libANGLE/Framebuffer.cpp
index 3e005b3..2aadbf6 100644
--- a/src/libANGLE/Framebuffer.cpp
+++ b/src/libANGLE/Framebuffer.cpp
@@ -84,7 +84,7 @@
     return nullptr;
 }
 
-FramebufferAttachment *Framebuffer::Data::getColorAttachment(unsigned int colorAttachment)
+const FramebufferAttachment *Framebuffer::Data::getColorAttachment(unsigned int colorAttachment) const
 {
     ASSERT(colorAttachment < mColorAttachments.size());
     return mColorAttachments[colorAttachment].isAttached() ?
@@ -92,32 +92,17 @@
            nullptr;
 }
 
-const FramebufferAttachment *Framebuffer::Data::getColorAttachment(unsigned int colorAttachment) const
-{
-    return const_cast<Framebuffer::Data *>(this)->getColorAttachment(colorAttachment);
-}
-
-FramebufferAttachment *Framebuffer::Data::getDepthAttachment()
+const FramebufferAttachment *Framebuffer::Data::getDepthAttachment() const
 {
     return mDepthAttachment.isAttached() ? &mDepthAttachment : nullptr;
 }
 
-const FramebufferAttachment *Framebuffer::Data::getDepthAttachment() const
-{
-    return const_cast<Framebuffer::Data *>(this)->getDepthAttachment();
-}
-
-FramebufferAttachment *Framebuffer::Data::getStencilAttachment()
+const FramebufferAttachment *Framebuffer::Data::getStencilAttachment() const
 {
     return mStencilAttachment.isAttached() ? &mStencilAttachment : nullptr;
 }
 
-const FramebufferAttachment *Framebuffer::Data::getStencilAttachment() const
-{
-    return const_cast<Framebuffer::Data *>(this)->getStencilAttachment();
-}
-
-FramebufferAttachment *Framebuffer::Data::getDepthStencilAttachment()
+const FramebufferAttachment *Framebuffer::Data::getDepthStencilAttachment() const
 {
     // A valid depth-stencil attachment has the same resource bound to both the
     // depth and stencil attachment points.
@@ -131,11 +116,6 @@
     return nullptr;
 }
 
-const FramebufferAttachment *Framebuffer::Data::getDepthStencilAttachment() const
-{
-    return const_cast<Framebuffer::Data *>(this)->getDepthStencilAttachment();
-}
-
 Framebuffer::Framebuffer(const Caps &caps, rx::ImplFactory *factory, GLuint id)
     : mData(caps),
       mImpl(nullptr),
@@ -178,41 +158,21 @@
     DetachMatchingAttachment(&mData.mStencilAttachment, resourceType, resourceId);
 }
 
-FramebufferAttachment *Framebuffer::getColorbuffer(unsigned int colorAttachment)
-{
-    return mData.getColorAttachment(colorAttachment);
-}
-
 const FramebufferAttachment *Framebuffer::getColorbuffer(unsigned int colorAttachment) const
 {
     return mData.getColorAttachment(colorAttachment);
 }
 
-FramebufferAttachment *Framebuffer::getDepthbuffer()
-{
-    return mData.getDepthAttachment();
-}
-
 const FramebufferAttachment *Framebuffer::getDepthbuffer() const
 {
     return mData.getDepthAttachment();
 }
 
-FramebufferAttachment *Framebuffer::getStencilbuffer()
-{
-    return mData.getStencilAttachment();
-}
-
 const FramebufferAttachment *Framebuffer::getStencilbuffer() const
 {
     return mData.getStencilAttachment();
 }
 
-FramebufferAttachment *Framebuffer::getDepthStencilBuffer()
-{
-    return mData.getDepthStencilAttachment();
-}
-
 const FramebufferAttachment *Framebuffer::getDepthStencilBuffer() const
 {
     return mData.getDepthStencilAttachment();
@@ -243,7 +203,7 @@
 {
     if (attachment >= GL_COLOR_ATTACHMENT0 && attachment <= GL_COLOR_ATTACHMENT15)
     {
-        return getColorbuffer(attachment - GL_COLOR_ATTACHMENT0);
+        return mData.getColorAttachment(attachment - GL_COLOR_ATTACHMENT0);
     }
     else
     {
@@ -251,13 +211,13 @@
         {
           case GL_COLOR:
           case GL_BACK:
-            return getColorbuffer(0);
+            return mData.getColorAttachment(0);
           case GL_DEPTH:
           case GL_DEPTH_ATTACHMENT:
-            return getDepthbuffer();
+            return mData.getDepthAttachment();
           case GL_STENCIL:
           case GL_STENCIL_ATTACHMENT:
-            return getStencilbuffer();
+            return mData.getStencilAttachment();
           case GL_DEPTH_STENCIL:
           case GL_DEPTH_STENCIL_ATTACHMENT:
             return getDepthStencilBuffer();