Refactor AOT deduplication steps so they can run before an app-jit snapshot as well.

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "lib/stacktrace.h"
@@ skipping 6793 matching lines @@
   if (isolate_snapshot_instructions_buffer == NULL) {
     RETURN_NULL_ERROR(instructions_snapshot_blob_size);
   }
   // Finalize all classes if needed.
   Dart_Handle state = Api::CheckAndFinalizePendingClasses(T);
   if (::Dart_IsError(state)) {
     return state;
   }
   I->StopBackgroundCompiler();
 
+  ProgramVisitor::Dedup();
   Symbols::Compact(I);
 
   NOT_IN_PRODUCT(TimelineDurationScope tds2(T, Timeline::GetIsolateStream(),
                                             "WriteAppJITSnapshot"));
   BlobImageWriter isolate_image_writer(isolate_snapshot_instructions_buffer,
                                        ApiReallocate,
                                        2 * MB /* initial_size */);
   FullSnapshotWriter writer(Snapshot::kAppJIT, NULL,
                             isolate_snapshot_data_buffer, ApiReallocate, NULL,
                             &isolate_image_writer);
@@ skipping 17 matching lines @@
 }
 
 
 DART_EXPORT void Dart_DumpNativeStackTrace(void* context) {
 #ifndef PRODUCT
   Profiler::DumpStackTrace(context);
 #endif
 }
 
 }  // namespace dart