Rename gl::Framebuffer::Data to gl::FramebufferState.

Moving this out of the Framebuffer class allows us to forward-
declare it.

BUG=angleproject:1363

Change-Id: I91971c37a92151df508cdf7f0eb8c3e93506d112
Reviewed-on: https://chromium-review.googlesource.com/340741
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/FramebufferImpl_mock.h b/src/libANGLE/renderer/FramebufferImpl_mock.h
index 084c711..9d67687 100644
--- a/src/libANGLE/renderer/FramebufferImpl_mock.h
+++ b/src/libANGLE/renderer/FramebufferImpl_mock.h
@@ -20,7 +20,7 @@
 class MockFramebufferImpl : public rx::FramebufferImpl
 {
   public:
-    MockFramebufferImpl() : rx::FramebufferImpl(gl::Framebuffer::Data()) {}
+    MockFramebufferImpl() : rx::FramebufferImpl(gl::FramebufferState()) {}
     virtual ~MockFramebufferImpl() { destroy(); }
 
     MOCK_METHOD2(discard, gl::Error(size_t, const GLenum *));