[Icons NTP] Add chrome://large-icon host, which resizes icon and renders fallback.

chrome/browser/ui/webui/large_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/large_icon_source.h"
+
+#include <string>
+#include <vector>
+
+#include "base/memory/ref_counted_memory.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/large_icon_url_parser.h"
+#include "chrome/common/url_constants.h"
+#include "components/favicon/core/browser/favicon_service.h"
+#include "components/favicon_base/fallback_icon_style.h"
+#include "grit/platform_locale_settings.h"
+#include "net/url_request/url_request.h"
+#include "skia/ext/image_operations.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/gfx/codec/png_codec.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/gfx/image/image_png_rep.h"
+#include "ui/gfx/image/image_skia.h"
+
+namespace {
+
+int kDefaultLargeIconSize = 96;
+int kMaxLargeIconSize = 512;  // Arbitrary bound to safegard endpoint.

[beaudoin, 2015/03/17 23:08:36]

Looks really big. I'd be fine limiting it more. According to the Sebastien
Gabriel's spec we never need to go above 192x192.

[huangs, 2015/03/18 22:54:11]

Done.

+
+}  // namespace
+
+LargeIconSource::IconRequest::IconRequest() : size(kDefaultLargeIconSize) {
+}
+
+LargeIconSource::IconRequest::IconRequest(
+    const content::URLDataSource::GotDataCallback& callback_in,
+    const GURL& url_in,
+    int size_in)
+    : callback(callback_in),
+      url(url_in),
+      size(size_in) {
+}
+
+LargeIconSource::IconRequest::~IconRequest() {
+}
+
+LargeIconSource::LargeIconSource(Profile* profile)
+    : profile_(profile),
+      render_fallback_on_failure_(true) {

[beaudoin, 2015/03/17 23:08:36]

Overdesign? All constructors set it to true: take it out until you need it.

[huangs, 2015/03/18 22:54:11]

Done.

+  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");

[beaudoin, 2015/03/17 23:08:36]

Isn't there a better way to access the platform's default font? This looks
hardcoded...

[huangs, 2015/03/18 22:54:11]

That's the purpose of my refactoring CL
https://chromiumcodereview.appspot.com/313053007/

However, I'm deferring that CL to get prototype through.

[beaudoin, 2015/03/19 01:50:18]

Acknowledged.

+#else
+  font_list.push_back(l10n_util::GetStringUTF8(IDS_SANS_SERIF_FONT_FAMILY));
+#endif
+  fallback_icon_service_.reset(
+      new favicon_base::FallbackIconService(font_list));
+}
+
+LargeIconSource::~LargeIconSource() {
+}
+
+std::string LargeIconSource::GetSource() const {
+  return chrome::kChromeUILargeIconHost;
+}
+
+void LargeIconSource::StartDataRequest(
+    const std::string& path,
+    int render_process_id,
+    int render_frame_id,
+    const content::URLDataSource::GotDataCallback& callback) {
+  chrome::LargeIconUrlParser parser;
+  bool success = parser.Parse(path);
+  if (!success || parser.size_in_pixels() <= 0
+      || parser.size_in_pixels() > kMaxLargeIconSize) {

[beaudoin, 2015/03/17 23:08:36]

More conventional in Chrome to have the || on the previous line. (And the style
guide recommends it.)

[huangs, 2015/03/18 22:54:11]

Done.

+    SendNotFoundResponse(callback);
+    return;
+  }
+
+  FaviconService* favicon_service = FaviconServiceFactory::GetForProfile(
+      profile_, ServiceAccessType::EXPLICIT_ACCESS);
+  if (!favicon_service) {
+    SendNotFoundResponse(callback);

[beaudoin, 2015/03/17 23:08:36]

Do we want to send a fallback icon in this case? (Given the URL is valid.)

[huangs, 2015/03/18 22:54:11]

|favicon_service| this is an exceptional case.  Better to send broken result to
amplify bug, than to hide it.

[beaudoin, 2015/03/19 01:50:18]

Acknowledged.

+    return;
+  }
+
+  GURL url(parser.url_string());
+  if (!url.is_valid()) {
+    SendNotFoundResponse(callback);
+    return;
+  }
+
+  favicon_service->GetGenericLargeIconForPageURL(
+      url,
+      parser.size_in_pixels(),
+      base::Bind(
+          &LargeIconSource::OnIconDataAvailable,
+          base::Unretained(this),
+          IconRequest(callback, url, parser.size_in_pixels())),
+      &cancelable_task_tracker_);
+}
+
+std::string LargeIconSource::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 LargeIconSource::ShouldReplaceExistingSource() const {
+  // Leave the existing DataSource in place, otherwise we'll drop any pending
+  // requests on the floor.
+  return false;
+}
+
+bool LargeIconSource::ShouldServiceRequest(
+    const net::URLRequest* request) const {
+  if (request->url().SchemeIs(chrome::kChromeSearchScheme))
+    return InstantIOContext::ShouldServiceRequest(request);
+  return URLDataSource::ShouldServiceRequest(request);
+}
+
+void LargeIconSource::OnIconDataAvailable(
+    const IconRequest& request,
+    const favicon_base::FaviconRawBitmapResult& bitmap_result) {
+  if (!bitmap_result.is_valid()) {
+    OnIconDataError(request);
+    return;
+  }
+    // Resize the retrieved large icon.

[beaudoin, 2015/03/17 23:08:36]

Indentation.

[huangs, 2015/03/18 22:54:11]

Can remove resizing code thanks to your insight in
https://codereview.chromium.org/1018733002/ :)

[beaudoin, 2015/03/19 01:50:18]

Acknowledged.

+  std::vector<gfx::ImagePNGRep> png_reps;
+  png_reps.push_back(gfx::ImagePNGRep(bitmap_result.bitmap_data, 1.0f));
+  gfx::Image image(png_reps);
+  if (image.IsEmpty()) {
+    OnIconDataError(request);
+    return;
+  }
+
+  SkBitmap resized_bitmap =
+      skia::ImageOperations::Resize(*image.ToSkBitmap(),
+                                    skia::ImageOperations::RESIZE_LANCZOS3,
+                                    request.size,
+                                    request.size);
+
+  // Send resized bitmap to the networking system.
+  std::vector<unsigned char> bitmap_data;
+  if (!gfx::PNGCodec::EncodeBGRASkBitmap(
+          resized_bitmap, false, &bitmap_data)) {
+    OnIconDataError(request);
+    return;
+  }
+
+  request.callback.Run(base::RefCountedBytes::TakeVector(&bitmap_data));
+}
+
+void LargeIconSource::OnIconDataError(const IconRequest& request) {
+  if (render_fallback_on_failure_)
+    SendFallbackIcon(request);
+  else
+    SendNotFoundResponse(request.callback);
+}
+
+
+void LargeIconSource::SendFallbackIcon(const IconRequest& request) {
+  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(
+          request.url, request.size, style);
+  request.callback.Run(base::RefCountedBytes::TakeVector(&bitmap_data));
+}
+
+void LargeIconSource::SendNotFoundResponse(
+    const content::URLDataSource::GotDataCallback& callback) {
+  callback.Run(nullptr);
+}