Add/resurrect support for bundles of WebStore items.

chrome/browser/safe_image_fetcher.cc

+// Copyright 2015 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 "chrome/browser/safe_image_fetcher.h"
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/message_loop/message_loop_proxy.h"
+#include "net/base/load_flags.h"
+#include "net/url_request/url_fetcher.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+
+SafeImageFetcher::SafeImageFetcher(
+    const GURL& url,
+    net::URLRequestContextGetter* context_getter,
+    const GetImageCallback& callback)
+    : ImageRequest(base::MessageLoopProxy::current()),
+      callback_(callback) {
+  if (url.is_valid()) {
+    DCHECK(context_getter);
+    url_fetcher_.reset(net::URLFetcher::Create(
+        url, net::URLFetcher::GET, this));
+    url_fetcher_->SetRequestContext(context_getter);
+    url_fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SAVE_COOKIES |
+                               net::LOAD_DO_NOT_SEND_COOKIES);
+
+    url_fetcher_->Start();
+    // We'll get called back in OnURLFetchComplete.
+  } else {
+    base::MessageLoopProxy::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&SafeImageFetcher::OnDecodeImageFailed,
+                   base::Unretained(this)));

[asargent_no_longer_on_chrome, 2015/03/26 18:12:50]

What if this object is deleted by its owner before this task gets a chance to
run? I think we should either make this class vend a weak ptr to itself here,
become fully ref-counted, or explicitly state in the class overview comment that
it's unsafe to delete until after the callback it was passed has been called
back. 

[Marc Treib, 2015/03/27 11:52:12]

Hm, just adding a comment feels like asking for trouble, and it's not what other
similar classes do. Full refcounting seems like overkill. So I've gone the
weak_ptr route.

+  }
+}
+
+SafeImageFetcher::~SafeImageFetcher() {
+}
+
+void SafeImageFetcher::OnURLFetchComplete(const net::URLFetcher* source) {
+  DCHECK_EQ(url_fetcher_.get(), source);
+  int response_code =
+      source->GetStatus().is_success() ? source->GetResponseCode() : 0;
+  if (!source->GetStatus().is_success() ||
+      response_code / 100 == 4 || response_code / 100 == 5) {
+    OnDecodeImageFailed();
+  } else {
+    std::string response_data;
+    source->GetResponseAsString(&response_data);
+
+    ImageDecoder::Start(this, response_data);
+  }
+  url_fetcher_.reset();
+}
+
+void SafeImageFetcher::OnImageDecoded(const SkBitmap& decoded_image) {
+  callback_.Run(decoded_image);
+}
+
+void SafeImageFetcher::OnDecodeImageFailed() {
+  callback_.Run(SkBitmap());
+}