[wasm] Add a flag --wasm-opt to test optimizations in the WASM pipeline.

src/compiler/pipeline.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_PIPELINE_H_
 #define V8_COMPILER_PIPELINE_H_
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
 // Do not include anything from src/compiler here!
 #include "src/globals.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 
 class CompilationInfo;
 class CompilationJob;
 class RegisterConfiguration;
 
 namespace compiler {
 
 class CallDescriptor;
+class JSGraph;
 class Graph;
 class InstructionSequence;
 class Schedule;
 class SourcePositionTable;
 
 class Pipeline : public AllStatic {
  public:
   // Returns a new compilation job for the given function.
   static CompilationJob* NewCompilationJob(Handle<JSFunction> function);
 
   // Returns a new compilation job for the WebAssembly compilation info.
   static CompilationJob* NewWasmCompilationJob(
-      CompilationInfo* info, Graph* graph, CallDescriptor* descriptor,
+      CompilationInfo* info, JSGraph* jsgraph, CallDescriptor* descriptor,
       SourcePositionTable* source_positions);
 
   // Run the pipeline on a machine graph and generate code. The {schedule} must
   // be valid, hence the given {graph} does not need to be schedulable.
   static Handle<Code> GenerateCodeForCodeStub(Isolate* isolate,
                                               CallDescriptor* call_descriptor,
                                               Graph* graph, Schedule* schedule,
                                               Code::Flags flags,
                                               const char* debug_name);
 
@@ skipping 21 matching lines @@
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(Pipeline);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_PIPELINE_H_