Move MimeTypeResourceHandler before ThrottlingResourceHandler

content/browser/loader/mime_type_resource_handler.h

Index: content/browser/loader/mime_type_resource_handler.h
diff --git a/content/browser/loader/mime_type_resource_handler.h b/content/browser/loader/mime_type_resource_handler.h
index f5581a6a8072522363e1f61e1030129b3ec9d4f2..5c0e770f30b4e77ba1340d5517cfb9681a99f846 100644
--- a/content/browser/loader/mime_type_resource_handler.h
+++ b/content/browser/loader/mime_type_resource_handler.h
@@ -19,15 +19,9 @@ class URLRequest;
 }
 
 namespace content {
-class PluginService;
-class ResourceDispatcherHostImpl;
-struct WebPluginInfo;
 
 // ResourceHandler that, if necessary, buffers a response body without passing
 // it to the next ResourceHandler until it can perform mime sniffing on it.
-// Once a response's MIME type is known, initiates special handling of the
-// response if needed (starts downloads, sends data to some plugin types via a
-// special channel).
 //
 // Uses the buffer provided by the original event handler for buffering, and
 // continues to reuses it until it can determine the MIME type
@@ -38,22 +32,36 @@ struct WebPluginInfo;
 // Before a request is sent, this ResourceHandler will also set an appropriate
 // Accept header on the request based on its ResourceType, if one isn't already
 // present.
-class CONTENT_EXPORT MimeTypeResourceHandler
-    : public LayeredResourceHandler,
-      public ResourceController {
+class CONTENT_EXPORT MimeTypeResourceHandler : public LayeredResourceHandler,

[mmenke, 2016/06/09 18:09:29]

Think this can now be renamed to MimeSniffingResourceHandler, since that's all
it does now.

[clamy, 2016/06/21 16:14:15]

Done.

+                                               public ResourceController {
  public:
-  // If ENABLE_PLUGINS is defined, |plugin_service| must not be NULL.
   MimeTypeResourceHandler(std::unique_ptr<ResourceHandler> next_handler,
-                          ResourceDispatcherHostImpl* host,
-                          PluginService* plugin_service,
                           net::URLRequest* request);
   ~MimeTypeResourceHandler() override;
 
  private:
+  enum State {
+    // Starting state of the MimeTypeResourceHandler. In this state, it is
+    // acting as a blind pass-through ResourceHandler.

[mmenke, 2016/06/09 18:09:29]

It's not a blind pass-through ResourceHandler.  It switches to STATE_BUFFERING
in OnResponseStarted.

[clamy, 2016/06/21 16:14:15]

Clarified this in the comment.

+    STATE_STARTING,
+
+    // In this state, the MimeTypeResourceHandler is buffering the response
+    // data in read_buffer_.
+    STATE_BUFFERING,
+
+    // In this state, the MimeTypeResourceHandler is replaying the buffered
+    // OnResponseStarted event to the downstream ResourceHandlers.
+    STATE_REPLAYING_RESPONSE_RECEIVED,
+
+    // In this state, the MimeTypeResourceHandler is just a blind pass-through
+    // ResourceHandler.
+    STATE_STREAMING,
+  };
+
   // ResourceHandler implementation:
   void SetController(ResourceController* controller) override;
-  bool OnResponseStarted(ResourceResponse* response, bool* defer) override;
   bool OnWillStart(const GURL&, bool* defer) override;
+  bool OnResponseStarted(ResourceResponse* response, bool* defer) override;
   bool OnWillRead(scoped_refptr<net::IOBuffer>* buf,
                   int* buf_size,
                   int min_size) override;
@@ -68,70 +76,23 @@ class CONTENT_EXPORT MimeTypeResourceHandler
   void CancelAndIgnore() override;
   void CancelWithError(int error_code) override;
 
-  bool ProcessResponse(bool* defer);
+  // Replays the buffered data to the downstream ResourceHandlers.
+  bool ProcessReplay(bool* defer);
+  bool ReplayResponseReceived(bool* defer);
+  bool ReplayResponseReceivedNewHandler(bool* defer);
+  bool ReplayReadCompleted(bool* defer);
 
   bool ShouldSniffContent();
   bool DetermineMimeType();
-  // Determines whether a plugin will handle the current request, and if so,
-  // sets up the handler to direct the response to that plugin. Returns false
-  // if there is an error and the request should be cancelled and true
-  // otherwise. |defer| is set to true if plugin data is stale and needs to be
-  // refreshed before the request can be handled (in this case the function
-  // still returns true). If the request is directed to a plugin,
-  // |handled_by_plugin| is set to true.
-  bool SelectPluginHandler(bool* defer, bool* handled_by_plugin);
-  // Returns false if the request should be cancelled.
-  bool SelectNextHandler(bool* defer);
-  bool UseAlternateNextHandler(std::unique_ptr<ResourceHandler> handler,
-                               const std::string& payload_for_old_handler);
-
-  bool ReplayReadCompleted(bool* defer);
-  void CallReplayReadCompleted();
 
-  bool MustDownload();
-
-  // Copies data from |read_buffer_| to |next_handler_|.
-  bool CopyReadBufferToNextHandler();
-
-  // Called on the IO thread once the list of plugins has been loaded.
-  void OnPluginsLoaded(const std::vector<WebPluginInfo>& plugins);
-
-  enum State {
-    STATE_STARTING,
-
-    // In this state, we are filling read_buffer_ with data for the purpose
-    // of sniffing the mime type of the response.
-    STATE_BUFFERING,
-
-    // In this state, we are select an appropriate downstream ResourceHandler
-    // based on the mime type of the response.  We are also potentially waiting
-    // for plugins to load so that we can determine if a plugin is available to
-    // handle the mime type.
-    STATE_PROCESSING,
-
-    // In this state, we are replaying buffered events (OnResponseStarted and
-    // OnReadCompleted) to the downstream ResourceHandler.
-    STATE_REPLAYING,
-
-    // In this state, we are just a blind pass-through ResourceHandler.
-    STATE_STREAMING
-  };
   State state_;
 
+  // Used to buffer the reponse received until replay.
   scoped_refptr<ResourceResponse> response_;
-  ResourceDispatcherHostImpl* host_;
-#if defined(ENABLE_PLUGINS)
-  PluginService* plugin_service_;
-#endif
   scoped_refptr<net::IOBuffer> read_buffer_;
   int read_buffer_size_;
   int bytes_read_;
 
-  bool must_download_;
-  bool must_download_is_set_;
-
-  base::WeakPtrFactory<MimeTypeResourceHandler> weak_ptr_factory_;
-
   DISALLOW_COPY_AND_ASSIGN(MimeTypeResourceHandler);
 };