Make JSONParser a pure interface.

chrome/browser/safe_json_parser_browsertest.cc

 // 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.
 
 #include "base/bind.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 #include "chrome/test/base/in_process_browser_test.h"
@@ skipping 36 matching lines @@
           base::Bind(&SafeJsonParserTest::ExpectValue, base::Unretained(this),
                      base::Passed(&value));
       error_callback = base::Bind(&SafeJsonParserTest::FailWithError,
                                   base::Unretained(this));
     } else {
       success_callback = base::Bind(&SafeJsonParserTest::FailWithValue,
                                     base::Unretained(this));
       error_callback = base::Bind(&SafeJsonParserTest::ExpectError,
                                   base::Unretained(this), error);
     }
-    scoped_refptr<SafeJsonParser> parser =
-        new SafeJsonParser(json, success_callback, error_callback);
-    parser->Start();
+    SafeJsonParser::Parse(json, success_callback, error_callback);
 
     message_loop_runner_->Run();
     message_loop_runner_ = nullptr;
   }
 
  private:
   void ExpectValue(scoped_ptr<base::Value> expected_value,
                    scoped_ptr<base::Value> actual_value) {
     EXPECT_TRUE(base::Value::Equals(actual_value.get(), expected_value.get()))
         << "Expected: " << MaybeToJson(expected_value.get())
@@ skipping 27 matching lines @@
   TestParse("\"laser\"");
   TestParse("false");
   TestParse("null");
   TestParse("3.14");
   TestParse("[");
   TestParse("\"");
   TestParse(std::string());
   TestParse("☃");
   TestParse("\"☃\"");
 }