Refactor ResourceHandler API.

content/browser/loader/resource_loader.h

Index: content/browser/loader/resource_loader.h
diff --git a/content/browser/loader/resource_loader.h b/content/browser/loader/resource_loader.h
index 6ebcd2de50b08624c9cf4cb2eae356f015916135..7a92c14fb35ce990e4ee052d92eaaf8e1bafb14f 100644
--- a/content/browser/loader/resource_loader.h
+++ b/content/browser/loader/resource_loader.h
@@ -14,7 +14,6 @@
 #include "content/browser/ssl/ssl_client_auth_handler.h"
 #include "content/browser/ssl/ssl_error_handler.h"
 #include "content/common/content_export.h"
-#include "content/public/browser/resource_controller.h"
 #include "net/url_request/url_request.h"
 
 namespace net {
@@ -32,8 +31,7 @@ class ResourceRequestInfoImpl;
 // chain of ResourceHandlers, and is the ResourceController for its handler.
 class CONTENT_EXPORT ResourceLoader : public net::URLRequest::Delegate,
                                       public SSLErrorHandler::Delegate,
-                                      public SSLClientAuthHandler::Delegate,
-                                      public ResourceController {
+                                      public SSLClientAuthHandler::Delegate {
  public:
   ResourceLoader(std::unique_ptr<net::URLRequest> request,
                  std::unique_ptr<ResourceHandler> handler,
@@ -53,6 +51,9 @@ class CONTENT_EXPORT ResourceLoader : public net::URLRequest::Delegate,
   void ClearLoginDelegate();
 
  private:
+  // ResourceController implementation for the ResourceLoader.
+  class Controller;
+
   // net::URLRequest::Delegate implementation:
   void OnReceivedRedirect(net::URLRequest* request,
                           const net::RedirectInfo& redirect_info,
@@ -75,11 +76,18 @@ class CONTENT_EXPORT ResourceLoader : public net::URLRequest::Delegate,
   void ContinueWithCertificate(net::X509Certificate* cert) override;
   void CancelCertificateSelection() override;
 
-  // ResourceController implementation:
-  void Resume() override;
-  void Cancel() override;
-  void CancelAndIgnore() override;
-  void CancelWithError(int error_code) override;
+  // These correspond to Controller's methods.
+  // TODO(mmenke):  Seems like this could be simplified a little.
+
+  // |is_continuation| is false if called from a ResourceController, and true if
+  // called from ResourceLoader, right after the previous operation succeeded.
+  // In the latter case, the ResourceController's Resume() method was called
+  // synchronously by the ResourceLoader, and the stack has since been unwound,
+  // so the ResourceLoader is at the top of the stack.
+  void Resume(bool is_continuation);
+  void Cancel();
+  void CancelAndIgnore();
+  void CancelWithError(int error_code);
 
   void StartRequestInternal();
   void CancelRequestInternal(int error, bool from_renderer);
@@ -108,6 +116,12 @@ class CONTENT_EXPORT ResourceLoader : public net::URLRequest::Delegate,
 
   enum DeferredStage {
     DEFERRED_NONE,
+    // Magic deferral "stage" which means that the code is currently in a
+    // recursive call from the ResourceLoader. When in this state, Resume() does
+    // nothing but update the deferral state, and when the stack is unwound back
+    // up to the ResourceLoader, the request will be continued. This is used to
+    // prevent the stack from getting too deep.
+    DEFERRED_SYNC,
     DEFERRED_START,
     DEFERRED_REDIRECT,
     DEFERRED_READ,
@@ -116,6 +130,8 @@ class CONTENT_EXPORT ResourceLoader : public net::URLRequest::Delegate,
   };
   DeferredStage deferred_stage_;
 
+  class ScopedDeferral;
+
   std::unique_ptr<net::URLRequest> request_;
   std::unique_ptr<ResourceHandler> handler_;
   ResourceLoaderDelegate* delegate_;