mojo: Add DataURLFetcher for processing data: urls.

mojo/fetcher/data_fetcher.h

Index: mojo/fetcher/data_fetcher.h
diff --git a/mojo/fetcher/about_fetcher.h b/mojo/fetcher/data_fetcher.h
similarity index 59%
copy from mojo/fetcher/about_fetcher.h
copy to mojo/fetcher/data_fetcher.h
index 456125a284ef22f573cbc5e0d31380d1ee7fc8a2..b94b796489f2d7f5aaeea4f44b67c76cfdc6cd82 100644
--- a/mojo/fetcher/about_fetcher.h
+++ b/mojo/fetcher/data_fetcher.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef MOJO_FETCHER_ABOUT_FETCHER_H_
-#define MOJO_FETCHER_ABOUT_FETCHER_H_
+#ifndef MOJO_FETCHER_DATA_FETCHER_H_
+#define MOJO_FETCHER_DATA_FETCHER_H_
 
 #include "mojo/shell/fetcher.h"
 
@@ -14,24 +14,16 @@
 namespace mojo {
 namespace fetcher {
 
-// Implements Fetcher for about: URLs.
-class AboutFetcher : public shell::Fetcher {
+// Implements Fetcher for data: URLs.
+class DataFetcher : public shell::Fetcher {
  public:
-  static const char kAboutScheme[];
-  static const char kAboutBlankURL[];
-
   static void Start(const GURL& url, const FetchCallback& loader_callback);
 
  private:
-  AboutFetcher(const GURL& url, const FetchCallback& loader_callback);
-  ~AboutFetcher() override;
-
-  void BuildResponse();
+  DataFetcher(const GURL& url, const FetchCallback& loader_callback);
+  ~DataFetcher() override;
 
-  // Must be called exactly once to run the loader callback (asynchrously). On
-  // success, the ownership of this object is passed to the loader callback;
-  // otherwise, the callback is run with a nullptr and this object is destroyed.
-  void PostToRunCallback(bool success);
+  void BuildAndDispatchResponse();
 
   // shell::Fetcher implementation.
   const GURL& GetURL() const override;
@@ -49,10 +41,10 @@ class AboutFetcher : public shell::Fetcher {
   const GURL url_;
   URLResponsePtr response_;
 
-  DISALLOW_COPY_AND_ASSIGN(AboutFetcher);
+  DISALLOW_COPY_AND_ASSIGN(DataFetcher);
 };
 
 }  // namespace fetcher
 }  // namespace mojo
 
-#endif  // MOJO_FETCHER_ABOUT_FETCHER_H_
+#endif  // MOJO_FETCHER_DATA_FETCHER_H_