Move iOS ImageFetcher to ios/web/public

ios/chrome/browser/suggestions/image_fetcher_impl.mm

 // 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 "ios/chrome/browser/suggestions/image_fetcher_impl.h"
 
 #include <UIKit/UIKit.h>
 
+#include "base/memory/ptr_util.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "components/image_fetcher/image_fetcher_delegate.h"
-#include "ios/chrome/browser/net/image_fetcher.h"
+#include "ios/web/public/image_fetcher/raw_image_fetcher.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "skia/ext/skia_utils_ios.h"
 #include "ui/gfx/image/image.h"
 
 namespace suggestions {
 
 ImageFetcherImpl::ImageFetcherImpl(
     net::URLRequestContextGetter* url_request_context,
-    base::SequencedWorkerPool* blocking_pool) {
-  imageFetcher_.reset(new ::ImageFetcher(blocking_pool));
-  imageFetcher_->SetRequestContextGetter(url_request_context);
+    base::SequencedWorkerPool* blocking_pool)
+    : image_fetcher_(base::MakeUnique<web::RawImageFetcher>(blocking_pool)) {
+  image_fetcher_->SetRequestContextGetter(url_request_context);
 }
 
 ImageFetcherImpl::~ImageFetcherImpl() {
 }
 
 void ImageFetcherImpl::SetImageFetcherDelegate(
     image_fetcher::ImageFetcherDelegate* delegate) {
   DCHECK(delegate);
   delegate_ = delegate;
 }
@@ skipping 12 matching lines @@
   if (image_url.is_empty()) {
     gfx::Image empty_image;
     callback.Run(id, empty_image);
     if (delegate_) {
       delegate_->OnImageFetched(id, empty_image);
     }
     return;
   }
   // Copy string reference so it's retained.
   const std::string fetch_id(id);
-  ImageFetchedCallback fetcher_callback =
+  web::ImageFetchedCallback fetcher_callback =
       ^(const GURL& original_url, int response_code, NSData* data) {
-      if (data) {
-        // Most likely always returns 1x images.
-        UIImage* ui_image = [UIImage imageWithData:data scale:1];
-        if (ui_image) {
-          gfx::Image gfx_image(ui_image);
-          callback.Run(fetch_id, gfx_image);
-          if (delegate_) {
-            delegate_->OnImageFetched(fetch_id, gfx_image);
+        if (data) {
+          // Most likely always returns 1x images.
+          UIImage* ui_image = [UIImage imageWithData:data scale:1];
+          if (ui_image) {
+            gfx::Image gfx_image(ui_image);
+            callback.Run(fetch_id, gfx_image);
+            if (delegate_) {

[sdefresne, 2016/11/25 09:27:50]

This is a block that keep a pointer to a C++ object (via "delegate_" which is a
member variable of "this", so it keep a reference to "this"). This is usually
really dangerous as the C++ object may be destroyed before the block is invoked.
Especially troubling here since StartDownload is obviously an asynchronous API.

After looking at RawImageFetcher, I see that the request is cancelled if the
object is destroyed, so this is probably okay. Can you add a comment above this
block so that reviewers don't have to go spelunking every time they review this
code?

[gambard, 2016/11/25 13:24:27]

Thanks, done.

+              delegate_->OnImageFetched(fetch_id, gfx_image);
+            }
+            return;
           }
-          return;
         }
-      }
-      gfx::Image empty_image;
-      callback.Run(fetch_id, empty_image);
-      if (delegate_) {
-        delegate_->OnImageFetched(fetch_id, empty_image);
-      }
-  };
-  imageFetcher_->StartDownload(image_url, fetcher_callback);
+        gfx::Image empty_image;
+        callback.Run(fetch_id, empty_image);
+        if (delegate_) {
+          delegate_->OnImageFetched(fetch_id, empty_image);
+        }
+      };
+  image_fetcher_->StartDownload(image_url, fetcher_callback);
 }
 
 }  // namespace suggestions