1. Get rid of SwitchIsolateScope as it is not clear when this should be used and there is also a bu…

runtime/vm/isolate.h

 // 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.
 
 #ifndef VM_ISOLATE_H_
 #define VM_ISOLATE_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/atomic.h"
@@ skipping 905 matching lines @@
     }
   }
 
  private:
   Isolate* new_isolate_;
   Isolate* saved_isolate_;
 
   DISALLOW_COPY_AND_ASSIGN(StartIsolateScope);
 };
 
-// When we need to temporarily become another isolate, we use the
-// SwitchIsolateScope.  It is not permitted to run dart code while in
-// a SwitchIsolateScope.
-class SwitchIsolateScope {
- public:
-  explicit SwitchIsolateScope(Isolate* new_isolate)
-      : new_isolate_(new_isolate),
-        saved_isolate_(Isolate::Current()),
-        saved_stack_limit_(saved_isolate_
-                           ? saved_isolate_->saved_stack_limit() : 0) {
-    // TODO(koda): Audit users; why would these two ever be equal?
-    if (saved_isolate_ != new_isolate_) {
-      if (new_isolate_ == NULL) {
-        Thread::ExitIsolate();
-      } else {
-        Thread::EnterIsolate(new_isolate_);
-        // Don't allow dart code to execute.
-        new_isolate_->SetStackLimit(~static_cast<uword>(0));
-      }
-    }
-  }
-
-  ~SwitchIsolateScope() {
-    if (saved_isolate_ != new_isolate_) {
-      if (new_isolate_ != NULL) {
-        Thread::ExitIsolate();
-      }
-      if (saved_isolate_ != NULL) {
-        Thread::EnterIsolate(saved_isolate_);
-        saved_isolate_->SetStackLimit(saved_stack_limit_);
-      }
-    }
-  }
-
- private:
-  Isolate* new_isolate_;
-  Isolate* saved_isolate_;
-  uword saved_stack_limit_;
-
-  DISALLOW_COPY_AND_ASSIGN(SwitchIsolateScope);
-};
-
 
 class IsolateSpawnState {
  public:
   IsolateSpawnState(Dart_Port parent_port,
                     const Function& func,
                     const Instance& message,
                     bool paused,
                     bool errorsAreFatal,
                     Dart_Port onExit,
                     Dart_Port onError);
@@ skipping 46 matching lines @@
   uint8_t* serialized_message_;
   intptr_t serialized_message_len_;
   Isolate::Flags isolate_flags_;
   bool paused_;
   bool errors_are_fatal_;
 };
 
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_