Move implementation from header to source.

net/base/filter.h

 // Copyright (c) 2006-2008 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.
 //
 // Filter performs filtering on data streams. Sample usage:
 //
 //   IStream* pre_filter_source;
 //   ...
 //   Filter* filter = Filter::Factory(filter_type, size);
 //   int pre_filter_data_len = filter->stream_buffer_size();
@@ skipping 44 matching lines @@
  public:
   // Enum to control what histograms are emitted near end-of-life of this
   // instance.
   enum StatisticSelector {
     SDCH_DECODE,
     SDCH_PASSTHROUGH,
     SDCH_EXPERIMENT_DECODE,
     SDCH_EXPERIMENT_HOLDBACK,
   };
 
-  virtual ~FilterContext() {}
+  virtual ~FilterContext();
 
   // What mime type was specified in the header for this data?
   // Only makes senses for some types of contexts, and returns false
   // when not applicable.
   virtual bool GetMimeType(std::string* mime_type) const = 0;
 
   // What URL was used to access this data?
   // Return false if gurl is not present.
   virtual bool GetURL(GURL* gurl) const = 0;
 
@@ skipping 183 matching lines @@
 
   // Context data from the owner of this filter.  Some filters need additional
   // context information (mime type, etc.) to properly function, and they access
   // this data via this reference member.
   const FilterContext& filter_context_;
 
   DISALLOW_COPY_AND_ASSIGN(Filter);
 };
 
 #endif  // NET_BASE_FILTER_H__