cc: Turn SharedQuadState into a struct-like class similar to DrawQuads.

cc/test/mock_quad_culler.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/test/mock_quad_culler.h"
 
 namespace cc {
 
 MockQuadCuller::MockQuadCuller()
     : m_activeQuadList(m_quadListStorage)
@@ skipping 15 matching lines @@
 {
     if (!drawQuad->rect.IsEmpty()) {
         m_activeQuadList.append(drawQuad.Pass());
         return true;
     }
     return false;
 }
 
 SharedQuadState* MockQuadCuller::useSharedQuadState(scoped_ptr<SharedQuadState> sharedQuadState)
 {
-    sharedQuadState->id = m_activeSharedQuadStateList.size();
-
     SharedQuadState* rawPtr = sharedQuadState.get();
     m_activeSharedQuadStateList.append(sharedQuadState.Pass());
     return rawPtr;
 }
 
 } // namespace cc