analysis/code clean (#11964)

Author: Superjomn

paddle/fluid/inference/analysis/README.md

@@ -54,4 +54,5 @@ It can be used as a helper class that draws the modified graph after each pass.
 There is some helper legacy/function/class for analysis.
 
 - [dot.h](./dot.h) give a easy to use interface for generating `DOT` codes,
-- [graph_traits.h](./graph_traits.h) contains the graph traversal algorithms, it uses `iterator` to make the algorithms easy to share across different passes.
+- [graph_traits.h](./graph_traits.h) contains the interfaces of the graph traversal algorithms, it uses `iterator`to make the algorithms easy to share across different passes,
+there are some implementations in  [data_flow_graph.cc](./data_flow_graph.cc) , such as BFS and DFS..

paddle/fluid/inference/analysis/pass.h

@@ -32,19 +32,6 @@ class Pass {
  public:
   Pass() = default;
   virtual ~Pass() = default;
-  // Virtual method overridden by subclasses to do only necessary initialization
-  // before any pass is run.
-  // virtual bool Initialize() { return false; }
-  // There is some passes such as FlowToDataFlowGraphPass that needs a
-  // ProgramDesc. Here use the native ProgramDesc ProtoBuf message, so that it
-  // only couple with the proto file.
-  // virtual bool Initialize(const framework::proto::ProgramDesc &desc) { return
-  // false; }
-  // There are some Passes such as DataFlowGraphToFluidPass that will output a
-  // ProgramDesc.
-  // virtual bool Initialize(framework::proto::ProgramDesc *desc) { return
-  // false; }
-
   // Mutable Pass.
   virtual bool Initialize(Argument *argument) { return false; }
   // Readonly Pass.