cc: Increment the ref count when assigning the SkImageFilter

cc/render_surface_impl.cc

Index: cc/render_surface_impl.cc
diff --git a/cc/render_surface_impl.cc b/cc/render_surface_impl.cc
index d61d448c10a0d14b005a56a563e7f949efe97d25..2d4e2f12fa243c5dc2774d446322aadaf4938973 100644
--- a/cc/render_surface_impl.cc
+++ b/cc/render_surface_impl.cc
@@ -187,7 +187,7 @@ void RenderSurfaceImpl::appendRenderPasses(RenderPassSink& passSink)
     scoped_ptr<RenderPass> pass = RenderPass::Create();
     pass->SetNew(renderPassId(), m_contentRect, m_damageTracker->currentDamageRect(), m_screenSpaceTransform);
     pass->filters = m_owningLayer->filters();
-    pass->filter = m_owningLayer->filter();
+    SkRefCnt_SafeAssign(pass->filter, m_owningLayer->filter());
     pass->background_filters = m_owningLayer->backgroundFilters();
     passSink.appendRenderPass(pass.Pass());
 }