Share FBO state with object and Impl.

This patch introduces a new Framebuffer::Data class, which stores
attachment related state. This will eliminate the need to store
duplicated state between the classes.

BUG=angleproject:930

Change-Id: I80de4db39ab99d623b0ad8306bf3cbb794cd8bd5
Reviewed-on: https://chromium-review.googlesource.com/254100
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/gl/FramebufferGL.cpp b/src/libANGLE/renderer/gl/FramebufferGL.cpp
index b96123e..0af069a 100644
--- a/src/libANGLE/renderer/gl/FramebufferGL.cpp
+++ b/src/libANGLE/renderer/gl/FramebufferGL.cpp
@@ -13,8 +13,8 @@
 namespace rx
 {
 
-FramebufferGL::FramebufferGL()
-    : FramebufferImpl()
+FramebufferGL::FramebufferGL(const gl::Framebuffer::Data &data)
+    : FramebufferImpl(data)
 {}
 
 FramebufferGL::~FramebufferGL()