content: Cleanup class/struct forward declarations

content/child/indexed_db/mock_webidbcallbacks.h

 // Copyright 2015 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 CONTENT_CHILD_INDEXED_DB_MOCK_WEBIDBCALLBACKS_H_
 #define CONTENT_CHILD_INDEXED_DB_MOCK_WEBIDBCALLBACKS_H_
 
 #include "base/macros.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "third_party/WebKit/public/platform/WebBlobInfo.h"
 #include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBCallbacks.h"
 #include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBDatabaseError.h"
 #include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBMetadata.h"
 #include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBValue.h"
 #include "third_party/WebKit/public/web/WebHeap.h"
 
-namespace blink {
-class WebData;
-}  // namespace blink
-
 namespace content {
 
 class MockWebIDBCallbacks : public blink::WebIDBCallbacks {
  public:
   MockWebIDBCallbacks();
   ~MockWebIDBCallbacks();
   MOCK_METHOD1(onError, void(const blink::WebIDBDatabaseError&));
   MOCK_METHOD3(onSuccess,
                void(const blink::WebIDBKey& key,
                     const blink::WebIDBKey& primaryKey,
@@ skipping 20 matching lines @@
                     blink::WebString dataLossMessage));
   MOCK_METHOD0(detach, void());
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockWebIDBCallbacks);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_INDEXED_DB_MOCK_WEBIDBCALLBACKS_H_