Split Renderbuffer::setStorage into two functions to match the API.

BUG=angleproject:886

Change-Id: I74375351339464b450c2f058adbeed7a1ba18cdd
Reviewed-on: https://chromium-review.googlesource.com/262125
Reviewed-by: Brandon Jones <bajones@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/renderer/gl/RenderbufferGL.cpp b/src/libANGLE/renderer/gl/RenderbufferGL.cpp
index b082ad7..88d4789 100644
--- a/src/libANGLE/renderer/gl/RenderbufferGL.cpp
+++ b/src/libANGLE/renderer/gl/RenderbufferGL.cpp
@@ -20,7 +20,13 @@
 RenderbufferGL::~RenderbufferGL()
 {}
 
-gl::Error RenderbufferGL::setStorage(GLsizei width, GLsizei height, GLenum internalformat, GLsizei samples)
+gl::Error RenderbufferGL::setStorage(GLenum internalformat, size_t width, size_t height)
+{
+    UNIMPLEMENTED();
+    return gl::Error(GL_INVALID_OPERATION);
+}
+
+gl::Error RenderbufferGL::setStorageMultisample(size_t samples, GLenum internalformat, size_t width, size_t height)
 {
     UNIMPLEMENTED();
     return gl::Error(GL_INVALID_OPERATION);