Implement DownloadImage directly in WebStateImpl

ios/web/web_state/web_state_impl.mm

Index: ios/web/web_state/web_state_impl.mm
diff --git a/ios/web/web_state/web_state_impl.mm b/ios/web/web_state/web_state_impl.mm
index 2be723464c9b10db360e5099e61e6be65c25390e..48e3b145d457de0ebbad88b63a8e2a94dfeb318c 100644
--- a/ios/web/web_state/web_state_impl.mm
+++ b/ios/web/web_state/web_state_impl.mm
@@ -16,6 +16,7 @@
 #include "ios/web/navigation/navigation_item_impl.h"
 #include "ios/web/net/request_group_util.h"
 #include "ios/web/public/browser_state.h"
+#include "ios/web/public/image_fetcher/raw_image_fetcher.h"
 #import "ios/web/public/java_script_dialog_presenter.h"
 #include "ios/web/public/navigation_item.h"
 #include "ios/web/public/url_util.h"
@@ -33,7 +34,10 @@
 #import "ios/web/webui/web_ui_ios_controller_factory_registry.h"
 #import "ios/web/webui/web_ui_ios_impl.h"
 #include "net/http/http_response_headers.h"
+#include "net/url_request/url_fetcher.h"
 #include "services/service_manager/public/cpp/interface_registry.h"
+#include "skia/ext/skia_utils_ios.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 
 namespace web {
 
@@ -63,6 +67,8 @@ WebStateImpl::WebStateImpl(BrowserState* browser_state)
       weak_factory_(this) {
   GlobalWebStateEventTracker::GetInstance()->OnWebStateCreated(this);
   web_controller_.reset([[CRWWebController alloc] initWithWebState:this]);
+  image_fetcher_.reset(new RawImageFetcher(web::WebThread::GetBlockingPool()));
+  image_fetcher_->SetRequestContextGetter(browser_state->GetRequestContext());
 }
 
 WebStateImpl::~WebStateImpl() {
@@ -538,9 +544,30 @@ int WebStateImpl::DownloadImage(
   // cookies or not. Currently, only downloads without cookies are supported.
   // |bypass_cache| is ignored since the downloads never go through a cache.
   DCHECK(is_favicon);
-  return [[web_controller_ delegate] downloadImageAtUrl:url
-                                          maxBitmapSize:max_bitmap_size
-                                              callback:callback];
+
+  static int g_download_id = 0;

[Eugene But (OOO till 7-30), 2016/11/30 17:13:50]

nit: g_ prefix means "global", so please don't use it here. 

[gambard, 2016/12/01 15:14:21]

Done.

+  int localDownloadId = ++g_download_id;

[Eugene But (OOO till 7-30), 2016/11/30 17:13:50]

s/localDownloadId/local_download_id

Same comments for other names

[gambard, 2016/12/01 15:14:21]

Done.

+  __block web::WebState::ImageDownloadCallback localImageCallback = callback;
+  __block GURL localUrl(url);
+  ImageFetchedCallback localCallback =
+      ^(const GURL& originalUrl, const int responseCode, NSData* data) {

[Eugene But (OOO till 7-30), 2016/11/30 17:13:50]

nit: you can drop |originalUrl|

[gambard, 2016/12/01 15:14:21]

Done.

+        std::vector<SkBitmap> frames;
+        std::vector<gfx::Size> sizes;
+        if (data) {
+          frames = skia::ImageDataToSkBitmaps(data);
+          for (auto& frame : frames) {
+            sizes.push_back(gfx::Size(frame.width(), frame.height()));
+          }
+        }
+        if (responseCode != net::URLFetcher::RESPONSE_CODE_INVALID) {
+          localImageCallback.Run(localDownloadId, responseCode, localUrl,
+                                 frames, sizes);
+        }

[Eugene But (OOO till 7-30), 2016/11/30 17:13:50]

We should also call callback for failure cases, unless there is a good reason
for not doing that (and if that's the case we should document that in API
comments). BTW, does content calls this callback for failure cases?

[gambard, 2016/12/01 15:14:21]

This is not for failure. From the comments on the enum: // Imposible http
response code. Used to signal that no http response code was received.
From what I understood of content they are calling the callback every time.

+      };
+  // |imageFetcher_| may have been reset if the tab got closed.

[Eugene But (OOO till 7-30), 2016/11/30 17:13:50]

Please don't mention tab here, web does not know anything about tabs.

[gambard, 2016/12/01 15:14:21]

Done.

+  if (image_fetcher_)
+    image_fetcher_->StartDownload(url, localCallback);
+  return g_download_id;
 }
 
 service_manager::InterfaceRegistry* WebStateImpl::GetMojoInterfaceRegistry() {