[Favicon] Add new fallback icon rendering flow.

components/favicon_base/fallback_icon_service.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 "components/favicon_base/fallback_icon_service.h"
+
+#include <algorithm>
+
+#include "base/i18n/case_conversion.h"
+#include "base/strings/utf_string_conversions.h"
+#include "components/favicon_base/favicon_types.h"
+#include "grit/platform_locale_settings.h"
+#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
+#include "third_party/skia/include/core/SkPaint.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/codec/png_codec.h"
+#include "ui/gfx/font_list.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/size.h"
+#include "url/gurl.h"
+
+namespace favicon_base {
+
+namespace {
+
+const int kMaxFallbackFaviconSize = 288;
+
+// Returns a single character to represent a page URL. To do this we take the
+// first letter in a domain's name and make it upper case.
+// TODO(huangs): Handle non-ASCII ("xn--") domain names.
+base::string16 GetFallbackIconText(const GURL& url) {
+  std::string domain = net::registry_controlled_domains::GetDomainAndRegistry(
+        url, net::registry_controlled_domains::INCLUDE_PRIVATE_REGISTRIES);
+  return domain.empty() ? base::string16() :
+      base::i18n::ToUpper(base::ASCIIToUTF16(std::string(1, domain[0])));
+}
+
+}  // namespace
+
+FallbackIconService::FallbackIconService() {
+  std::string font_name =
+      l10n_util::GetStringUTF8(IDS_SANS_SERIF_FONT_FAMILY);
+#if defined(OS_CHROMEOS)
+  const std::string kChromeOSFontFamily = "Noto Sans";
+  font_name = kChromeOSFontFamily;
+#endif
+  fallback_icon_font_list_.push_back(font_name);
+}
+
+FallbackIconService::~FallbackIconService() {
+}
+
+std::vector<unsigned char> FallbackIconService::RenderFallbackIconBitmap(
+    const GURL& icon_url,
+    int size,
+    const FallbackIconStyle& style) {
+  int size_to_use = std::min(kMaxFallbackFaviconSize, size);
+  gfx::Canvas canvas(gfx::Size(size_to_use, size_to_use), 1.0f, false);
+  DrawFallbackIcon(icon_url, size_to_use, style, &canvas);
+
+  std::vector<unsigned char> bitmap_data;
+  if (!gfx::PNGCodec::EncodeBGRASkBitmap(canvas.ExtractImageRep().sk_bitmap(),
+                                         false, &bitmap_data)) {
+    bitmap_data.clear();
+  }
+  return bitmap_data;
+}
+
+void FallbackIconService::DrawFallbackIcon(const GURL& icon_url,
+                                           int size,
+                                           const FallbackIconStyle& style,
+                                           gfx::Canvas* canvas) {
+  const int x = 0;
+  const int y = 0;
+  SkPaint paint;
+  paint.setStyle(SkPaint::kFill_Style);
+  paint.setAntiAlias(true);
+
+  // Draw a filled, colored rounded square. Not limiting |size|.

[pkotwicz, 2015/01/23 20:43:38]

I am confused as to what "Not limiting |size|" means. If it means that
DrawFallbackIcon() doesn't check if |size| is below kMaxFallbackFaviconSize, I
think it is ok to remove the comment

[huangs, 2015/01/26 21:34:56]

Done.

+  paint.setColor(style.background_color);
+  int corner_radius = static_cast<int>(size * style.roundness * 0.5 + 0.5);
+  canvas->DrawRoundRect(gfx::Rect(x, y, size, size),
+      corner_radius, paint);
+
+  // Draw text.
+  base::string16 icon_text = GetFallbackIconText(icon_url);
+  if (!icon_text.empty()) {
+    int font_size = static_cast<int>(size * style.font_size_ratio);
+    if (font_size > 0) {
+      // TODO(huangs): See how expensive gfx::FontList() is, and possibly cache.
+      canvas->DrawStringRectWithFlags(
+          icon_text,
+          gfx::FontList(fallback_icon_font_list_, gfx::Font::NORMAL, font_size),
+          style.text_color,
+          gfx::Rect(x, y, size, size),
+          gfx::Canvas::TEXT_ALIGN_CENTER);
+    }
+  }
+}
+
+}  // namespace favicon_base