[Icons NTP] Refactor large_icon_source to extract the logic shared between desktop and Android to a new large_icon_service.

This is required since the Android implementation of the icon-based NTP will rely on custom Java code to render the fallback. As a result we want to share the logic needed to retrieve large icons and to compute the fallback style without needing them to go through the full-featured chrome://large-icon that performs the rendering of fallback icons. The Java code will hook directly into the large_icon_service.

This CL also fixes a bug, making sure only non-square icons can be returned as large icons.

Besides this, this CL doesn't change the behavior but will make it possible to add the large icon selection logic to large_icon_service where it can be shared with the Android code.

BUG=467712

Review URL: https://codereview.chromium.org/1092873002

Cr-Commit-Position: refs/heads/master@{#326325}

9 files changed, 217 insertions, 8 deletions

diff --git a/components/favicon.gypi b/components/favicon.gypi
index d150316..d2f9195 100644
--- a/components/favicon.gypi
+++ b/components/favicon.gypi
@@ -36,6 +36,8 @@
         'favicon/core/favicon_service.h',
         'favicon/core/favicon_url.cc',
         'favicon/core/favicon_url.h',
+        'favicon/core/large_icon_service.cc',
+        'favicon/core/large_icon_service.h',
       ],
       'include_dirs': [
         '..',
diff --git a/components/favicon/core/BUILD.gn b/components/favicon/core/BUILD.gn
index 7f9b762..f4e8a15e 100644
--- a/components/favicon/core/BUILD.gn
+++ b/components/favicon/core/BUILD.gn
@@ -19,6 +19,8 @@ static_library("core") {
     "favicon_service.h",
     "favicon_url.cc",
     "favicon_url.h",
+    "large_icon_service.cc",
+    "large_icon_service.h",
   ]
 
   deps = [
diff --git a/components/favicon/core/large_icon_service.cc b/components/favicon/core/large_icon_service.cc
new file mode 100644
index 0000000..702761c
--- /dev/null
+++ b/components/favicon/core/large_icon_service.cc
@@ -0,0 +1,77 @@
+// 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/core/large_icon_service.h"
+
+#include "components/favicon/core/favicon_service.h"
+#include "components/favicon_base/fallback_icon_style.h"
+#include "components/favicon_base/favicon_types.h"
+
+namespace favicon {
+
+LargeIconService::LargeIconService(FaviconService* favicon_service)
+    : favicon_service_(favicon_service) {
+  large_icon_types_.push_back(favicon_base::IconType::FAVICON);
+  large_icon_types_.push_back(favicon_base::IconType::TOUCH_ICON);
+  large_icon_types_.push_back(favicon_base::IconType::TOUCH_PRECOMPOSED_ICON);
+}
+
+LargeIconService::~LargeIconService() {
+}
+
+base::CancelableTaskTracker::TaskId
+    LargeIconService::GetLargeIconOrFallbackStyle(
+        const GURL& page_url,
+        int desired_size_in_pixel,
+        const favicon_base::LargeIconCallback& callback,
+        base::CancelableTaskTracker* tracker) {
+  // TODO(beaudoin): For now this is just a wrapper around
+  //   GetLargestRawFaviconForPageURL. Add the logic required to select the best
+  //   possible large icon. Also add logic to fetch-on-demand when the URL of
+  //   a large icon is known but its bitmap is not available.
+  return favicon_service_->GetLargestRawFaviconForPageURL(
+      page_url,
+      large_icon_types_,
+      desired_size_in_pixel,
+      base::Bind(&LargeIconService::RunLargeIconCallback,
+                 base::Unretained(this), callback, desired_size_in_pixel),
+      tracker);
+}
+
+void LargeIconService::RunLargeIconCallback(
+    const favicon_base::LargeIconCallback& callback,
+    int desired_size_in_pixel,
+    const favicon_base::FaviconRawBitmapResult& bitmap_result) {
+  // If there are no bitmaps, return a result with an empty |bitmap| and a
+  // default |fallback_icon_style|.
+  favicon_base::LargeIconResult result;
+  if (!bitmap_result.is_valid()) {
+    callback.Run(result);
+    return;
+  }
+
+  // If there is a bitmap but it's smaller than the requested size or
+  // non-square, compute its dominant color and use it as background in
+  // |fallback_icon_style|.
+  if (bitmap_result.pixel_size.width() < desired_size_in_pixel ||
+      bitmap_result.pixel_size.height() < desired_size_in_pixel ||
+      bitmap_result.pixel_size.width() != bitmap_result.pixel_size.height()) {
+    // TODO(beaudoin): Resize the icon if it's large enough. Alternatively,
+    // return it and let the HTML resize it.
+    result.fallback_icon_style.reset(new favicon_base::FallbackIconStyle());
+    favicon_base::SetDominantColorAsBackground(
+        bitmap_result.bitmap_data, result.fallback_icon_style.get());
+    callback.Run(result);
+    return;
+  }
+
+  // The bitmap is square and at least as large as the requested one, return
+  // it.
+  // TODO(beaudoin): Resize the icon if it's too large. Alternatively, return
+  // it and let the HTML resize it.
+  result.bitmap = bitmap_result;
+  callback.Run(result);
+}
+
+}  // namespace favicon
diff --git a/components/favicon/core/large_icon_service.h b/components/favicon/core/large_icon_service.h
new file mode 100644
index 0000000..1063fd7
--- /dev/null
+++ b/components/favicon/core/large_icon_service.h
@@ -0,0 +1,65 @@
+// Copyright (c) 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.
+
+#ifndef COMPONENTS_FAVICON_CORE_LARGE_ICON_SERVICE_H_
+#define COMPONENTS_FAVICON_CORE_LARGE_ICON_SERVICE_H_
+
+#include <vector>
+
+#include "base/task/cancelable_task_tracker.h"
+#include "components/favicon_base/favicon_callback.h"
+#include "components/keyed_service/core/keyed_service.h"
+
+class GURL;
+
+namespace favicon_base {
+struct FaviconRawBitmapResult;
+}
+
+namespace favicon {
+
+class FaviconService;
+
+// The large icon service provides methods to access large icons. It relies on
+// the favicon service.
+class LargeIconService : public KeyedService {
+ public:
+  explicit LargeIconService(FaviconService* favicon_service);
+
+  ~LargeIconService() override;
+
+  // Requests the best large icon for the page at |page_url| given the requested
+  // |desired_size_in_pixel|. If no good large icon can be found, returns the
+  // fallback style to use, for which the background is set to the dominant
+  // color of a smaller icon when one is available. This function returns the
+  // style of the fallback icon rather than the rendered version so that clients
+  // can render the icon themselves.
+  base::CancelableTaskTracker::TaskId GetLargeIconOrFallbackStyle(
+    const GURL& page_url,
+    int desired_size_in_pixel,
+    const favicon_base::LargeIconCallback& callback,
+    base::CancelableTaskTracker* tracker);
+
+ private:
+  // Intermediate callback for GetLargeIconOrFallbackStyle(). Ensures the large
+  // icon is at least the desired size, if not compute the icon fallback style
+  // and use it to invoke |callback|.
+  void RunLargeIconCallback(
+      const favicon_base::LargeIconCallback& callback,
+      int desired_size_in_pixel,
+      const favicon_base::FaviconRawBitmapResult& bitmap_result);
+
+  FaviconService* favicon_service_;
+
+  // A pre-populated list of the types of icon files to consider when looking
+  // for large icons. This is an optimization over populating an icon type
+  // vector on each request.
+  std::vector<int> large_icon_types_;
+
+  DISALLOW_COPY_AND_ASSIGN(LargeIconService);
+};
+
+}  // namespace favicon
+
+#endif  // COMPONENTS_FAVICON_CORE_LARGE_ICON_SERVICE_H_
diff --git a/components/favicon_base/fallback_icon_style.cc b/components/favicon_base/fallback_icon_style.cc
index e620613..d3e395b 100644
--- a/components/favicon_base/fallback_icon_style.cc
+++ b/components/favicon_base/fallback_icon_style.cc
@@ -4,6 +4,9 @@
 
 #include "components/favicon_base/fallback_icon_style.h"
 
+#include <algorithm>
+
+#include "ui/gfx/color_analysis.h"
 #include "ui/gfx/color_utils.h"
 
 namespace favicon_base {
@@ -12,14 +15,19 @@ namespace {
 
 // Luminance threshold for background color determine whether to use dark or
 // light text color.
-int kDarkTextLuminanceThreshold = 190;
+const int kDarkTextLuminanceThreshold = 190;
+
+// The maximum luminance of the background color to ensure light text is
+// readable.
+const double kMaxBackgroundColorLuminance = 0.67;
 
 // Default values for FallbackIconStyle.
-SkColor kDefaultBackgroundColor = SkColorSetRGB(0x80, 0x80, 0x80);
-SkColor kDefaultTextColorDark = SK_ColorBLACK;
-SkColor kDefaultTextColorLight = SK_ColorWHITE;
-double kDefaultFontSizeRatio = 0.8;
-double kDefaultRoundness = 0.125;  // 1 / 8.
+const SkColor kDefaultBackgroundColor = SkColorSetRGB(0x78, 0x78, 0x78);
+const SkColor kDefaultTextColorDark = SK_ColorBLACK;
+const SkColor kDefaultTextColorLight = SK_ColorWHITE;
+const double kDefaultFontSizeRatio = 0.44;
+const double kDefaultRoundness = 0;  // Square. Round corners are applied
+                                     // externally (Javascript or Java).
 
 }  // namespace
 
@@ -45,4 +53,18 @@ bool ValidateFallbackIconStyle(const FallbackIconStyle& style) {
       style.roundness >= 0.0 && style.roundness <= 1.0;
 }
 
+void SetDominantColorAsBackground(
+    const scoped_refptr<base::RefCountedMemory>& bitmap_data,
+    FallbackIconStyle* style) {
+  SkColor dominant_color =
+      color_utils::CalculateKMeanColorOfPNG(bitmap_data);
+  // Assumes |style.text_color| is light, and clamps luminance down to a
+  // reasonable maximum value so text is readable.
+  color_utils::HSL color_hsl;
+  color_utils::SkColorToHSL(dominant_color, &color_hsl);
+  color_hsl.l = std::min(color_hsl.l, kMaxBackgroundColorLuminance);
+  style->background_color =
+      color_utils::HSLToSkColor(color_hsl, SK_AlphaOPAQUE);
+}
+
 }  // namespace favicon_base
diff --git a/components/favicon_base/fallback_icon_style.h b/components/favicon_base/fallback_icon_style.h
index 097636b..84842ed 100644
--- a/components/favicon_base/fallback_icon_style.h
+++ b/components/favicon_base/fallback_icon_style.h
@@ -5,6 +5,7 @@
 #ifndef COMPONENTS_FAVICON_BASE_FALLBACK_ICON_STYLE_H_
 #define COMPONENTS_FAVICON_BASE_FALLBACK_ICON_STYLE_H_
 
+#include "base/memory/ref_counted_memory.h"
 #include "third_party/skia/include/core/SkColor.h"
 
 namespace favicon_base {
@@ -37,6 +38,13 @@ void MatchFallbackIconTextColorAgainstBackgroundColor(FallbackIconStyle* style);
 // Returns whether |style| values are within bounds.
 bool ValidateFallbackIconStyle(const FallbackIconStyle& style);
 
+// Set |style|'s background color to the dominant color of |bitmap_data|,
+// clamping luminance down to a reasonable maximum value so that light text is
+// readable.
+void SetDominantColorAsBackground(
+    const scoped_refptr<base::RefCountedMemory>& bitmap_data,
+    FallbackIconStyle* style);
+
 }  // namespace favicon_base
 
 #endif  // COMPONENTS_FAVICON_BASE_FALLBACK_ICON_STYLE_H_
diff --git a/components/favicon_base/favicon_callback.h b/components/favicon_base/favicon_callback.h
index 7616a11..96029f1 100644
--- a/components/favicon_base/favicon_callback.h
+++ b/components/favicon_base/favicon_callback.h
@@ -13,6 +13,7 @@ namespace favicon_base {
 
 struct FaviconRawBitmapResult;
 struct FaviconImageResult;
+struct LargeIconResult;
 
 // Callback for functions that can be used to return a |gfx::Image| and the
 // |GURL| it is loaded from. They are returned as a |FaviconImageResult| object.
@@ -29,6 +30,11 @@ typedef base::Callback<void(const FaviconRawBitmapResult&)>
 typedef base::Callback<void(const std::vector<FaviconRawBitmapResult>&)>
     FaviconResultsCallback;
 
+// Callback for functions returning data for a large icon. |LargeIconResult|
+// will contain either the raw bitmap for a large icon or the style of the
+// fallback to use if a sufficiently large icon could not be found.
+typedef base::Callback<void(const LargeIconResult&)> LargeIconCallback;
+
 }  // namespace favicon_base
 
 #endif  // COMPONENTS_FAVICON_BASE_FAVICON_CALLBACK_H_
diff --git a/components/favicon_base/favicon_types.cc b/components/favicon_base/favicon_types.cc
index 0188f1e..e69f1d7 100644
--- a/components/favicon_base/favicon_types.cc
+++ b/components/favicon_base/favicon_types.cc
@@ -4,6 +4,8 @@
 
 #include "components/favicon_base/favicon_types.h"
 
+#include "components/favicon_base/fallback_icon_style.h"
+
 namespace favicon_base {
 
 // ---------------------------------------------------------
@@ -20,7 +22,13 @@ FaviconRawBitmapResult::FaviconRawBitmapResult()
     : expired(false), icon_type(INVALID_ICON) {
 }
 
-FaviconRawBitmapResult::~FaviconRawBitmapResult() {
-}
+FaviconRawBitmapResult::~FaviconRawBitmapResult() {}
+
+// --------------------------------------------------------
+// LargeIconResult
+
+LargeIconResult::LargeIconResult() {}
+
+LargeIconResult::~LargeIconResult() {}
 
 }  // namespace favicon_base
diff --git a/components/favicon_base/favicon_types.h b/components/favicon_base/favicon_types.h
index ea64754..f7c812a 100644
--- a/components/favicon_base/favicon_types.h
+++ b/components/favicon_base/favicon_types.h
@@ -6,12 +6,15 @@
 #define COMPONENTS_FAVICON_BASE_FAVICON_TYPES_H_
 
 #include "base/memory/ref_counted_memory.h"
+#include "base/memory/scoped_ptr.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/image/image.h"
 #include "url/gurl.h"
 
 namespace favicon_base {
 
+struct FallbackIconStyle;
+
 typedef int64 FaviconID;
 
 // Defines the icon types. They are also stored in icon_type field of favicons
@@ -72,6 +75,22 @@ struct FaviconRawBitmapResult {
 // HistoryBackend::SetFavicons().
 typedef FaviconRawBitmapResult FaviconRawBitmapData;
 
+// Result returned by LargeIconService::GetLargeIconOrFallbackStyle(). Contains
+// either the bitmap data if the favicon database has a sufficiently large
+// favicon bitmap and the style of the fallback icon otherwise.
+struct LargeIconResult {
+  LargeIconResult();
+  ~LargeIconResult();
+
+  // The bitmap from the favicon database if the database has a sufficiently
+  // large one.
+  FaviconRawBitmapResult bitmap;
+
+  // The fallback icon style if a sufficiently large icon isn't available. This
+  // uses the dominant color of a smaller icon as the background if available.
+  scoped_ptr<FallbackIconStyle> fallback_icon_style;
+};
+
 }  // namespace favicon_base
 
 #endif  // COMPONENTS_FAVICON_BASE_FAVICON_TYPES_H_