Simplify the ImageDataFetcher code.

BUG=609127

Review-Url: https://codereview.chromium.org/2073753002
Cr-Commit-Position: refs/heads/master@{#400642}

components/image_fetcher/image_data_fetcher.cc

@@ -6,7 +6,6 @@
 
 #include "net/base/load_flags.h"
 #include "net/url_request/url_fetcher.h"
-#include "net/url_request/url_fetcher_delegate.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "net/url_request/url_request_status.h"
@@ -14,71 +13,23 @@
 
 namespace image_fetcher {
 
-// An active image URL fetcher request. The class contains any related request
-// state and logic for handling a single image url request.
-class ImageDataFetcher::ImageDataFetcherRequest
-    : public net::URLFetcherDelegate {
- public:
-  ImageDataFetcherRequest(const GURL& url,
-                          const ImageDataFetcherCallback& callback,
-                          ImageDataFetcher* image_url_fetcher);
-  ~ImageDataFetcherRequest() override {}
+// An active image URL fetcher request. The struct contains the related requests
+// state.
+struct ImageDataFetcher::ImageDataFetcherRequest {
+  ImageDataFetcherRequest(const ImageDataFetcherCallback& callback,
+                          std::unique_ptr<net::URLFetcher> url_fetcher)
+    : callback(callback),
+      url_fetcher(std::move(url_fetcher)) {}
 
-  // Sends the URL requests.
-  void Start(net::URLRequestContextGetter* request_context);
-
- private:
-  // Method inherited from URLFetcherDelegate
-  void OnURLFetchComplete(const net::URLFetcher* source) override;
-
-  // The URL of the image to fetch.
-  const GURL url_;
+  ~ImageDataFetcherRequest() {}
 
   // The callback to run after the image data was fetched. The callback will
   // be run even if the image data could not be fetched successfully.
-  ImageDataFetcherCallback callback_;
-
-  // The ImageDataFetcher that owns the ImageDataFetcherRequest.
-  ImageDataFetcher* image_url_fetcher_;
+  ImageDataFetcherCallback callback;
 
-  std::unique_ptr<net::URLFetcher> url_fetcher_;
-
-  DISALLOW_COPY_AND_ASSIGN(ImageDataFetcherRequest);
+  std::unique_ptr<net::URLFetcher> url_fetcher;
 };
 
-ImageDataFetcher::ImageDataFetcherRequest::ImageDataFetcherRequest(
-    const GURL& url,
-    const ImageDataFetcherCallback& callback,
-    ImageDataFetcher* image_url_fetcher)
-    : url_(url),
-      callback_(callback),
-      image_url_fetcher_(image_url_fetcher) {
-}
-
-void ImageDataFetcher::ImageDataFetcherRequest::Start(
-    net::URLRequestContextGetter* request_context) {
-  DCHECK(!url_fetcher_);
-
-  url_fetcher_ = net::URLFetcher::Create(url_, net::URLFetcher::GET, this);
-  url_fetcher_->SetRequestContext(request_context);
-  url_fetcher_->Start();
-}
-
-void ImageDataFetcher::ImageDataFetcherRequest::OnURLFetchComplete(
-    const net::URLFetcher* source) {
-  // An empty string is passed to the callback in case on an unsuccessfull URL
-  // request.
-  std::string image_data;
-  if (source->GetStatus().status() == net::URLRequestStatus::SUCCESS) {
-    source->GetResponseAsString(&image_data);
-  }
-  callback_.Run(image_data);
-
-  // Remove the completed ImageDataFetcherRequest from the internal request
-  // queue. This must be last in the method.
-  image_url_fetcher_->RemoveImageDataFetcherRequest(url_);
-}
-
 ImageDataFetcher::ImageDataFetcher(
     net::URLRequestContextGetter* url_request_context_getter)
     : url_request_context_getter_(url_request_context_getter) {}
@@ -87,15 +38,29 @@ ImageDataFetcher::~ImageDataFetcher() {}
 
 void ImageDataFetcher::FetchImageData(
     const GURL& url, const ImageDataFetcherCallback& callback) {
+  std::unique_ptr<net::URLFetcher> url_fetcher =
+      net::URLFetcher::Create(url, net::URLFetcher::GET, this);
+
   std::unique_ptr<ImageDataFetcherRequest> request(
-      new ImageDataFetcherRequest(url, callback, this));
-  request->Start(url_request_context_getter_.get());
-  pending_requests_[url] = std::move(request);
+      new ImageDataFetcherRequest(callback, std::move(url_fetcher)));
+  request->url_fetcher->SetRequestContext(url_request_context_getter_.get());
+  request->url_fetcher->Start();
+
+  pending_requests_[request->url_fetcher.get()] = std::move(request);
 }
 
-void ImageDataFetcher::RemoveImageDataFetcherRequest(const GURL& image_url) {
-  size_t count = pending_requests_.erase(image_url);
-  DCHECK(count);
+void ImageDataFetcher::OnURLFetchComplete(const net::URLFetcher* source) {
+  auto request_iter = pending_requests_.find(source);
+  DCHECK(request_iter != pending_requests_.end());
+
+  std::string image_data;
+  if (source->GetStatus().status() == net::URLRequestStatus::SUCCESS) {
+    source->GetResponseAsString(&image_data);
+  }
+  request_iter->second->callback.Run(image_data);
+
+  // Remove the finished request.
+  pending_requests_.erase(request_iter);
 }
 
 }  // namespace image_fetcher

components/image_fetcher/image_data_fetcher.h

@@ -12,22 +12,24 @@
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "net/url_request/url_fetcher_delegate.h"
 #include "url/gurl.h"
 
 namespace net {
+class URLFetcher;
 class URLRequestContextGetter;
 }  // namespace net
 
 namespace image_fetcher {
 
-class ImageDataFetcher {
+class ImageDataFetcher : public net::URLFetcherDelegate {
  public:
   using ImageDataFetcherCallback =
       base::Callback<void(const std::string& image_data)>;
 
   explicit ImageDataFetcher(
       net::URLRequestContextGetter* url_request_context_getter);
-  ~ImageDataFetcher();
+  ~ImageDataFetcher() override;
 
   // Fetches the raw image bytes from the given |image_url| and calls the given
   // |callback|. The callback is run even if fetching the URL fails. In case
@@ -36,14 +38,13 @@ class ImageDataFetcher {
                       const ImageDataFetcherCallback& callback);
 
  private:
-  class ImageDataFetcherRequest;
+  struct ImageDataFetcherRequest;
 
-  // Removes the ImageDataFetcherRequest for the given |image_url| from the
-  // internal request queue.
-  void RemoveImageDataFetcherRequest(const GURL& image_url);
+  // Method inherited from URLFetcherDelegate
+  void OnURLFetchComplete(const net::URLFetcher* source) override;
 
   // All active image url requests.
-  std::map<const GURL, std::unique_ptr<ImageDataFetcherRequest>>
+  std::map<const net::URLFetcher*, std::unique_ptr<ImageDataFetcherRequest>>
       pending_requests_;
 
   scoped_refptr<net::URLRequestContextGetter> url_request_context_getter_;