[Extensions] DCHECK that ExtensionFunctions respond (and only once)

extensions/browser/api/test/test_api.h

 // Copyright 2014 The Chromium 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 EXTENSIONS_BROWSER_API_TEST_TEST_API_H_
 #define EXTENSIONS_BROWSER_API_TEST_TEST_API_H_
 
 #include "base/macros.h"
 #include "base/values.h"
 #include "extensions/browser/extension_function.h"
@@ skipping 45 matching lines @@
  public:
   DECLARE_EXTENSION_FUNCTION("test.log", UNKNOWN)
 
  protected:
   ~TestLogFunction() override;
 
   // TestExtensionFunction:
   bool RunSafe() override;
 };
 
-class TestSendMessageFunction : public AsyncExtensionFunction {
+class TestSendMessageFunction : public UIThreadExtensionFunction {
  public:
+  TestSendMessageFunction();
   DECLARE_EXTENSION_FUNCTION("test.sendMessage", UNKNOWN)
 
   // Sends a reply back to the calling extension. Many extensions don't need
   // a reply and will just ignore it.
   void Reply(const std::string& message);
 
   // Sends an error back to the calling extension.
   void ReplyWithError(const std::string& error);
 
  protected:
   ~TestSendMessageFunction() override;
 
-  // ExtensionFunction:
-  bool RunAsync() override;
+  // UIExtensionFunction:
+  ResponseAction Run() override;
+
+  // Whether or not the function is currently waiting for a reply.
+  bool waiting_;
+
+  ResponseValue response_;
 };
 
 class TestGetConfigFunction : public TestExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION("test.getConfig", UNKNOWN)
 
   // Set the dictionary returned by chrome.test.getConfig().
   // Does not take ownership of |value|.
   static void set_test_config_state(base::DictionaryValue* value);
 
@@ skipping 34 matching lines @@
  protected:
   ~TestWaitForRoundTripFunction() override;
 
   // TestExtensionFunction:
   bool RunSafe() override;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_TEST_TEST_API_H_