Avoid PNG encode/decode for Win8 tile logo creation

chrome/browser/ui/metro_pin_tab_helper_win.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/browser/ui/metro_pin_tab_helper_win.h"
 
 #include <set>
 
 #include "base/base_paths.h"
 #include "base/bind.h"
@@ skipping 13 matching lines @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
 #include "crypto/sha2.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/color_analysis.h"
 #include "ui/gfx/color_utils.h"
 #include "ui/gfx/image/image.h"
+#include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(MetroPinTabHelper)
 
 namespace {
 
 // Histogram name for site-specific tile pinning metrics.
 const char kMetroPinMetric[] = "Metro.SecondaryTilePin";
 
@@ skipping 26 matching lines @@
 bool CreateSiteSpecificLogo(const gfx::ImageSkia& image,
                             const string16& tile_id,
                             const FilePath& logo_dir,
                             FilePath* logo_path) {
   const int kLogoWidth = 120;
   const int kLogoHeight = 120;
   const int kBoxWidth = 40;
   const int kBoxHeight = 40;
   const int kCaptionHeight = 20;
   const double kBoxFade = 0.75;
-  const int kColorMeanDarknessLimit = 100;
-  const int kColorMeanLightnessLimit = 650;
 
   if (image.isNull())
     return false;
 
-  // First paint the image onto an opaque background to get rid of transparency.
-  // White is used as it will be disregarded in the mean calculation because of
-  // lightness limit.
+  // Fill the tile logo with the dominant color of the favicon bitmap.
+  SkColor dominant_color = color_utils::CalculateKMeanColorOfBitmap(
+      image.GetRepresentation(ui::SCALE_FACTOR_100P).sk_bitmap());
   SkPaint paint;
-  paint.setColor(SK_ColorWHITE);
-  gfx::Canvas favicon_canvas(gfx::Size(image.width(), image.height()),
-                             ui::SCALE_FACTOR_100P, true);
-  favicon_canvas.DrawRect(gfx::Rect(0, 0, image.width(), image.height()),
-                          paint);
-  favicon_canvas.DrawImageInt(image, 0, 0);
-
-  // Fill the tile logo with the average color from bitmap. To do this we need
-  // to work out the 'average color' which is calculated using PNG encoded data
-  // of the bitmap.
-  std::vector<unsigned char> icon_png;
-  if (!gfx::PNGCodec::EncodeBGRASkBitmap(
-          favicon_canvas.ExtractImageRep().sk_bitmap(), false, &icon_png)) {
-    return false;
-  }
-
-  scoped_refptr<base::RefCountedStaticMemory> icon_mem(
-      new base::RefCountedStaticMemory(&icon_png.front(), icon_png.size()));
-  color_utils::GridSampler sampler;
-  SkColor mean_color = color_utils::CalculateKMeanColorOfPNG(
-      icon_mem, kColorMeanDarknessLimit, kColorMeanLightnessLimit, &sampler);
-  paint.setColor(mean_color);
+  paint.setColor(dominant_color);
   gfx::Canvas canvas(gfx::Size(kLogoWidth, kLogoHeight), ui::SCALE_FACTOR_100P,
                      true);
   canvas.DrawRect(gfx::Rect(0, 0, kLogoWidth, kLogoHeight), paint);
 
   // Now paint a faded square for the favicon to go in.
   color_utils::HSL shift = {-1, -1, kBoxFade};
-  paint.setColor(color_utils::HSLShift(mean_color, shift));
+  paint.setColor(color_utils::HSLShift(dominant_color, shift));
   int box_left = (kLogoWidth - kBoxWidth) / 2;
   int box_top = (kLogoHeight - kCaptionHeight - kBoxHeight) / 2;
   canvas.DrawRect(gfx::Rect(box_left, box_top, kBoxWidth, kBoxHeight), paint);
 
   // Now paint the favicon into the tile, leaving some room at the bottom for
   // the caption.
   int left = (kLogoWidth - image.width()) / 2;
   int top = (kLogoHeight - kCaptionHeight - image.height()) / 2;
   canvas.DrawImageInt(image, left, top);
 
@@ skipping 347 matching lines @@
 
   GURL url = web_contents()->GetURL();
   string16 tile_id = GenerateTileId(UTF8ToUTF16(url.spec()));
   metro_un_pin_from_start_screen(tile_id,
                                  base::Bind(&PinPageReportUmaCallback));
 }
 
 void MetroPinTabHelper::FaviconDownloaderFinished() {
   favicon_chooser_.reset();
 }