[Icons NTP] Working prototype to fetch, store, and display big icons.

chrome/browser/ui/webui/big_icon_source.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/ui/webui/big_icon_source.h"
+
+#include <string>
+#include <vector>
+
+#include "base/memory/ref_counted_memory.h"
+#include "chrome/browser/favicon/favicon_service.h"
+#include "chrome/browser/favicon/favicon_service_factory.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/search/instant_io_context.h"
+#include "chrome/common/favicon/big_icon_url_parser.h"
+#include "chrome/common/url_constants.h"
+#include "components/favicon_base/fallback_icon_style.h"
+#include "grit/platform_locale_settings.h"
+#include "net/url_request/url_request.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/gfx/favicon_size.h"
+
+namespace {
+
+int kFallbackIconSize = 96;
+
+}  // namespace
+
+BigIconSource::IconRequest::IconRequest() : size(48) {
+}
+
+BigIconSource::IconRequest::IconRequest(
+    const content::URLDataSource::GotDataCallback& callback_in,
+    const GURL& path_in,
+    int size_in)
+    : callback(callback_in),
+      path(path_in),
+      size(size_in) {
+}
+
+BigIconSource::IconRequest::~IconRequest() {
+}
+
+BigIconSource::BigIconSource(Profile* profile)
+    : profile_(profile),
+      render_fallback_on_failure_(true) {
+  std::vector<std::string> font_list;
+#if defined(OS_CHROMEOS)
+  font_list.push_back("Noto Sans");
+#elif defined(OS_IOS)
+  font_list.push_back("Helvetica Neue");
+#else
+  font_list.push_back(l10n_util::GetStringUTF8(IDS_SANS_SERIF_FONT_FAMILY));
+#endif
+  fallback_icon_service_.reset(
+      new favicon_base::FallbackIconService(font_list));
+}
+
+BigIconSource::~BigIconSource() {
+}
+
+std::string BigIconSource::GetSource() const {
+  return chrome::kChromeUIBigIconHost;
+}
+
+void BigIconSource::StartDataRequest(
+    const std::string& path,
+    int render_process_id,
+    int render_frame_id,
+    const content::URLDataSource::GotDataCallback& callback) {
+  chrome::BigIconUrlParser parser;
+  bool success = parser.Parse(path);
+  if (!success) {
+    SendDefaultResponse(callback);
+    return;
+  }
+
+  FaviconService* favicon_service = FaviconServiceFactory::GetForProfile(
+      profile_, ServiceAccessType::EXPLICIT_ACCESS);
+  if (!favicon_service) {
+    SendDefaultResponse(callback);
+    return;
+  }
+
+  GURL url(parser.url_string());
+  if (!url.is_valid()) {
+    SendDefaultResponse(callback);
+    return;
+  }
+  favicon_service->HackGetBigIcon(
+      url,
+      parser.size_in_pixels(),
+      base::Bind(
+          &BigIconSource::OnBigIconDataAvailable,
+          base::Unretained(this),
+          IconRequest(callback, url, parser.size_in_pixels())),
+      &cancelable_task_tracker_);
+}
+
+std::string BigIconSource::GetMimeType(const std::string&) const {
+  // We need to explicitly return a mime type, otherwise if the user tries to
+  // drag the image they get no extension.
+  return "image/png";
+}
+
+bool BigIconSource::ShouldReplaceExistingSource() const {
+  // Leave the existing DataSource in place, otherwise we'll drop any pending
+  // requests on the floor.
+  return false;
+}
+
+bool BigIconSource::ShouldServiceRequest(
+    const net::URLRequest* request) const {
+  if (request->url().SchemeIs(chrome::kChromeSearchScheme))
+    return InstantIOContext::ShouldServiceRequest(request);
+  return URLDataSource::ShouldServiceRequest(request);
+}
+
+void BigIconSource::OnBigIconDataAvailable(
+    IconRequest request,
+    const favicon_base::FaviconRawBitmapResult& bitmap_result) {
+  if (bitmap_result.is_valid()) {
+    // TODO: Resize the big icon to request.size.
+    // Need to do so here because otherwise NTP can deduce by size whether user
+    // has visited a site!

[Roger McFarlane (Chromium), 2015/03/16 19:00:59]

assuming:

(1) non-privileged access is allowed from by NTP provider.
(2) raw bitmaps for the icon's don't match the requested sizes

[huangs, 2015/03/17 01:43:52]

Yup! Raw bitmap sizes are pretty much arbitrary.  Also the size is accessible if
bitmap contents are not.

+
+    // Forward the data along to the networking system.
+    request.callback.Run(bitmap_result.bitmap_data.get());
+  } else if (render_fallback_on_failure_) {
+    SendFallbackIcon(request.path, request.callback);
+  } else {
+    SendDefaultResponse(request.callback);
+  }
+}
+
+void BigIconSource::SendFallbackIcon(
+    const GURL& url,
+    const content::URLDataSource::GotDataCallback& callback) {
+  favicon_base::FallbackIconStyle style;
+  style.background_color = SkColorSetRGB(0xcc, 0xcc, 0xcc);
+  favicon_base::MatchFallbackIconTextColorAgainstBackgroundColor(&style);
+  style.roundness = 1.0;
+  std::vector<unsigned char> bitmap_data =
+      fallback_icon_service_->RenderFallbackIconBitmap(
+          url, kFallbackIconSize, style);
+  callback.Run(base::RefCountedBytes::TakeVector(&bitmap_data));
+}
+
+void BigIconSource::SendDefaultResponse(

[Roger McFarlane (Chromium), 2015/03/16 19:00:59]

is this really a default? or is it an error response?

[huangs, 2015/03/17 01:43:52]

Renamed.

+    const content::URLDataSource::GotDataCallback& callback) {
+  callback.Run(nullptr);
+}