Extract renderer-side favicon downloading code into separate helper class

chrome/renderer/favicon_helper.cc

+// Copyright (c) 2012 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/renderer/favicon_helper.h"
+
+#include "base/bind.h"
+#include "base/message_loop.h"
+#include "chrome/common/favicon_url.h"
+#include "chrome/common/icon_messages.h"
+#include "content/public/renderer/render_view.h"
+#include "net/base/data_url.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebFrame.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebURLRequest.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebVector.h"
+#include "ui/gfx/favicon_size.h"
+#include "ui/gfx/size.h"
+#include "ui/gfx/skbitmap_operations.h"
+#include "webkit/glue/image_decoder.h"
+#include "webkit/glue/multi_resolution_image_resource_fetcher.h"
+#include "webkit/glue/webkit_glue.h"
+
+using WebKit::WebURLRequest;
+using webkit_glue::MultiResolutionImageResourceFetcher;
+
+FaviconHelper::FaviconHelper(content::RenderView* render_view)
+    : content::RenderViewObserver(render_view) {
+}
+
+FaviconHelper::~FaviconHelper() {
+}
+
+void FaviconHelper::SendUpdateFaviconURL(int32 routing_id,
+                                         int32 page_id,
+                                         const std::vector<FaviconURL>& urls) {
+  if (!urls.empty()) {
+    Send(new IconHostMsg_UpdateFaviconURL(routing_id, page_id, urls));
+  }
+}
+
+bool FaviconHelper::OnMessageReceived(const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(FaviconHelper, message)
+    IPC_MESSAGE_HANDLER(IconMsg_DownloadFavicon, OnDownloadFavicon)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+
+  return handled;
+}
+
+void FaviconHelper::OnDownloadFavicon(int id,
+                                      const GURL& image_url,
+                                      int image_size) {
+  bool data_image_failed = false;
+  if (image_url.SchemeIs("data")) {
+    SkBitmap data_image = ImageFromDataUrl(image_url);
+    data_image_failed = data_image.empty();
+    if (!data_image_failed) {
+      std::vector<SkBitmap> images(1, data_image);
+      Send(new IconHostMsg_DidDownloadFavicon(
+          routing_id(), id, image_url, false, image_size, images));
+    }
+  }
+
+  if (data_image_failed ||
+      !DownloadFavicon(id, image_url, image_size)) {
+    Send(new IconHostMsg_DidDownloadFavicon(
+        routing_id(), id, image_url, true, image_size,
+        std::vector<SkBitmap>()));
+  }
+}
+
+bool FaviconHelper::DownloadFavicon(int id,
+                                    const GURL& image_url,
+                                    int image_size) {
+  // Make sure webview was not shut down.
+  if (!render_view()->GetWebView())
+    return false;
+  // Create an image resource fetcher and assign it with a call back object.
+  image_fetchers_.push_back(new MultiResolutionImageResourceFetcher(
+      image_url, render_view()->GetWebView()->mainFrame(), id,
+      WebURLRequest::TargetIsFavicon,
+      base::Bind(&FaviconHelper::DidDownloadFavicon,
+                 base::Unretained(this), image_size)));
+  return true;
+}
+
+void FaviconHelper::DidDownloadFavicon(
+    int requested_size,
+    MultiResolutionImageResourceFetcher* fetcher,
+    const std::vector<SkBitmap>& images) {
+  // Notify requester of image download status.
+  Send(new IconHostMsg_DidDownloadFavicon(routing_id(),
+                                          fetcher->id(),
+                                          fetcher->image_url(),
+                                          images.empty(),
+                                          requested_size,
+                                          images));
+
+  // Remove the image fetcher from our pending list. We're in the callback from
+  // MultiResolutionImageResourceFetcher, best to delay deletion.
+  ImageResourceFetcherList::iterator iter =
+      std::find(image_fetchers_.begin(), image_fetchers_.end(), fetcher);
+  if (iter != image_fetchers_.end()) {
+    image_fetchers_.erase(iter);
+    MessageLoop::current()->DeleteSoon(FROM_HERE, fetcher);
+  }
+}
+
+SkBitmap FaviconHelper::ImageFromDataUrl(const GURL& url) const {
+  std::string mime_type, char_set, data;
+  if (net::DataURL::Parse(url, &mime_type, &char_set, &data) && !data.empty()) {
+    // Decode the favicon using WebKit's image decoder.
+    webkit_glue::ImageDecoder decoder(
+        gfx::Size(gfx::kFaviconSize, gfx::kFaviconSize));
+    const unsigned char* src_data =
+        reinterpret_cast<const unsigned char*>(&data[0]);
+
+    return decoder.Decode(src_data, data.size());
+  }
+  return SkBitmap();
+}