Refactored loading of applications / extensions icons.

chrome/browser/extensions/image_loader.cc

Index: chrome/browser/extensions/image_loader.cc
diff --git a/chrome/browser/extensions/image_loader.cc b/chrome/browser/extensions/image_loader.cc
index 2c8f77cb4dad2d0d140c0d5116cb523ea9018799..f429b6f7186903745c26243c2ecd4890f8223ce7 100644
--- a/chrome/browser/extensions/image_loader.cc
+++ b/chrome/browser/extensions/image_loader.cc
@@ -7,6 +7,7 @@
 #include <map>
 #include <vector>
 
+#include "base/base64.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/file_util.h"
@@ -15,16 +16,26 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/extensions/image_loader_factory.h"
+#include "chrome/browser/favicon/favicon_service.h"
+#include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/extensions/extension.h"
+#include "chrome/common/extensions/extension_icon_set.h"
+#include "chrome/common/extensions/manifest_handlers/app_launch_info.h"
+#include "chrome/common/extensions/manifest_handlers/icons_handler.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/common/url_constants.h"
 #include "grit/chrome_unscaled_resources.h"
 #include "grit/component_extension_resources_map.h"
 #include "grit/theme_resources.h"
 #include "skia/ext/image_operations.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/codec/png_codec.h"
+#include "ui/gfx/color_utils.h"
+#include "ui/gfx/favicon_size.h"
 #include "ui/gfx/image/image_skia.h"
+#include "ui/gfx/size.h"
+#include "ui/gfx/skbitmap_operations.h"
 
 #if defined(USE_AURA)
 #include "ui/keyboard/keyboard_util.h"
@@ -115,6 +126,57 @@ void AddComponentResourceEntries(
   }
 }
 
+// Converts an bitmap image to a PNG representation.
+scoped_refptr<base::RefCountedMemory> BitmapToMemory(const SkBitmap* image) {
+  base::RefCountedBytes* image_bytes = new base::RefCountedBytes;
+  gfx::PNGCodec::EncodeBGRASkBitmap(*image, false, &image_bytes->data());
+  return image_bytes;
+}

[Finnur, 2013/09/30 15:11:21]

This function is now both here and in extension_icon_source.cc.

[dvh-g, 2013/10/01 04:19:26]

Done.

+
+// Returns a PNG image data URL of a given image.
+GURL GetImageDataURL(const gfx::Image& image) {
+  if (image.IsEmpty())
+    return GURL();
+
+  scoped_refptr<base::RefCountedMemory> mem =
+      BitmapToMemory(image.ToSkBitmap());
+  std::string contents_base64;
+  if (!base::Base64Encode(
+          std::string(reinterpret_cast<const char*>(mem->front()), mem->size()),
+          &contents_base64))
+    return GURL();
+
+  const char kDataURLPrefix[] = ":image/png;base64,";
+  return GURL(std::string(chrome::kDataScheme) + kDataURLPrefix +
+              contents_base64);
+}
+
+// Converts the image to grayscale.
+SkBitmap DesaturateImage(const SkBitmap* image) {
+  color_utils::HSL shift = {-1, 0, 0.6};
+  return SkBitmapOperations::CreateHSLShiftedBitmap(*image, shift);
+}
+
+// Creates an image from PNG data.
+SkBitmap* ToBitmap(const unsigned char* data, size_t size) {
+  SkBitmap* decoded = new SkBitmap();
+  bool success = gfx::PNGCodec::Decode(data, size, decoded);
+  DCHECK(success);
+  return decoded;
+}
+
+// Load an image from a resource given its identifier |resource_id|.
+SkBitmap* GetImageByResourceId(int resource_id) {
+  std::string contents = ResourceBundle::GetSharedInstance()
+      .GetRawDataResourceForScale(resource_id,
+                                  ui::SCALE_FACTOR_100P).as_string();
+
+  // Convert and return it.
+  const unsigned char* data =
+      reinterpret_cast<const unsigned char*>(contents.data());
+  return ToBitmap(data, contents.length());
+}
+
 }  // namespace
 
 namespace extensions {
@@ -165,8 +227,8 @@ ImageLoader::LoadResult::~LoadResult() {
 ////////////////////////////////////////////////////////////////////////////////
 // ImageLoader
 
-ImageLoader::ImageLoader()
-    : weak_ptr_factory_(this) {
+ImageLoader::ImageLoader(Profile* profile)
+    : weak_ptr_factory_(this), profile_(profile) {
 }
 
 ImageLoader::~ImageLoader() {
@@ -347,4 +409,261 @@ void ImageLoader::ReplyBack(
   callback.Run(image);
 }
 
+void ImageLoader::LoadExtensionIconAsync(
+    const extensions::Extension* extension,
+    int icon_size,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback) {
+  if (extension == NULL) {
+    LoadIconFailed(extension, icon_size, grayscale, callback);
+  }

[Finnur, 2013/09/30 15:11:21]

style: Single line body, no braces needed.

But under what circumstances would |extension| be NULL?

[dvh-g, 2013/10/01 04:19:26]

Added a comment.

+
+  ExtensionResource resource = IconsInfo::GetIconResource(
+      extension, icon_size, ExtensionIconSet::MATCH_BIGGER);
+  LoadImageAsync(extension,
+                 resource,
+                 gfx::Size(icon_size, icon_size),
+                 base::Bind(&ImageLoader::LoadExtensionIconLoaded,
+                            base::Unretained(this),
+                            extension,
+                            icon_size,
+                            grayscale,
+                            callback));
+}
+
+void ImageLoader::LoadExtensionIconLoaded(
+    const extensions::Extension* extension,
+    int icon_size,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback,
+    const gfx::Image& image) {
+  if (image.IsEmpty())
+    LoadIconFailed(extension, icon_size, grayscale, callback);
+  else
+    FinalizeImage(image, grayscale, callback);
+}
+
+void ImageLoader::LoadIconFailed(
+    const extensions::Extension* extension,
+    int icon_size,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback) {
+  if ((extension != NULL) &&
+      (icon_size == extension_misc::EXTENSION_ICON_BITTY))
+    LoadFaviconImage(extension, icon_size, grayscale, callback);
+  else
+    LoadDefaultImage(extension, icon_size, grayscale, callback);
+}
+
+void ImageLoader::LoadFaviconImage(
+    const extensions::Extension* extension,
+    int icon_size,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback) {
+  FaviconService* favicon_service =
+      FaviconServiceFactory::GetForProfile(profile_, Profile::EXPLICIT_ACCESS);
+  // Fall back to the default icons if the service isn't available.
+  if (favicon_service == NULL) {
+    LoadDefaultImage(extension, icon_size, grayscale, callback);
+    return;
+  }
+
+  GURL favicon_url = AppLaunchInfo::GetFullLaunchURL(extension);
+  favicon_service->GetRawFaviconForURL(
+      FaviconService::FaviconForURLParams(
+          profile_, favicon_url, chrome::FAVICON, gfx::kFaviconSize),
+      ui::SCALE_FACTOR_100P,
+      base::Bind(&ImageLoader::OnFaviconDataAvailable,
+                 base::Unretained(this),
+                 extension,
+                 icon_size,
+                 grayscale,
+                 callback),
+      &cancelable_task_tracker_);
+}
+
+void ImageLoader::OnFaviconDataAvailable(
+    const extensions::Extension* extension,
+    int icon_size,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback,
+    const chrome::FaviconBitmapResult& bitmap_result) {
+  // Fallback to the default icon if there wasn't a favicon.
+  if (!bitmap_result.is_valid()) {
+    LoadDefaultImage(extension, icon_size, grayscale, callback);
+    return;
+  }
+
+  gfx::Image image = gfx::Image::CreateFrom1xBitmap(*ToBitmap(
+      bitmap_result.bitmap_data->front(), bitmap_result.bitmap_data->size()));
+  if (!grayscale) {
+    // If we don't need a grayscale image, then we can bypass FinalizeImage
+    // to avoid unnecessary conversions.

[Finnur, 2013/09/30 15:11:21]

It seems we're not consistent in skipping the FinalizeImage call. See for
example LoadExtensionIconLoaded and LoadDefaultImageDone. Why not always call
FinalizeImage and let it determine (based on |grayscale|) whether it needs to
jump to the file thread or just call the callback directly? It seems like these
functions shouldn't need to make a judgement call based on |grayscale|, in case
Finalize does some more processing.

[dvh-g, 2013/10/01 04:19:26]

It was the behavior of the existing code in extension_icon_source.
Though, it's a good idea to simplify this code.

+    callback.Run(image);
+  } else {
+    FinalizeImage(image, grayscale, callback);
+  }
+}
+
+void ImageLoader::LoadDefaultImage(
+    const extensions::Extension* extension,
+    int icon_size,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback) {
+  content::BrowserThread::PostTask(
+      content::BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&ImageLoader::LoadDefaultImageOnFileThread,
+                 base::Unretained(this),
+                 extension,
+                 icon_size,
+                 grayscale,
+                 callback));
+}
+
+void ImageLoader::LoadDefaultImageOnFileThread(
+    const extensions::Extension* extension,
+    int icon_size,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback) {
+  const SkBitmap* default_image = NULL;
+  if ((extension == NULL) || (extension->is_app()))
+    default_image = GetDefaultAppImage();
+  else
+    default_image = GetDefaultExtensionImage();
+
+  SkBitmap result_image;
+  if (icon_size == -1) {
+    // If a specific size was not requested.
+    result_image = *default_image;
+  } else {
+    SkBitmap resized_image(
+        skia::ImageOperations::Resize(*default_image,
+                                      skia::ImageOperations::RESIZE_LANCZOS3,
+                                      icon_size,
+                                      icon_size));
+    // There are cases where Resize returns an empty bitmap, for example if you
+    // ask for an image too large. In this case it is better to return the
+    // default image than returning nothing at all.
+    if (resized_image.empty())
+      resized_image = *default_image;
+    result_image = resized_image;
+  }
+
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI,
+      FROM_HERE,
+      base::Bind(&ImageLoader::LoadDefaultImageDone,
+                 base::Unretained(this),
+                 gfx::Image::CreateFrom1xBitmap(result_image),
+                 grayscale,
+                 callback));
+}
+
+void ImageLoader::LoadDefaultImageDone(
+    const gfx::Image& image,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback) {
+  FinalizeImage(image, grayscale, callback);
+}
+
+void ImageLoader::FinalizeImage(
+    const gfx::Image& image,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback) {
+  content::BrowserThread::PostTask(
+      content::BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&ImageLoader::FinalizeImageOnFileThread,
+                 base::Unretained(this),
+                 image,
+                 grayscale,
+                 callback));
+}
+
+void ImageLoader::FinalizeImageOnFileThread(
+    const gfx::Image& image,
+    bool grayscale,
+    const base::Callback<void(const gfx::Image&)>& callback) {
+  SkBitmap bitmap;
+  if (grayscale)
+    bitmap = DesaturateImage(image.ToSkBitmap());
+  else
+    bitmap = *image.ToSkBitmap();
+
+  gfx::Image modifiedImage = gfx::Image::CreateFrom1xBitmap(bitmap);
+  content::BrowserThread::PostTask(content::BrowserThread::UI,
+                                   FROM_HERE,
+                                   base::Bind(&ImageLoader::FinalizeImageDone,
+                                              base::Unretained(this),
+                                              modifiedImage,
+                                              callback));
+}
+
+void ImageLoader::FinalizeImageDone(
+    const gfx::Image& image,
+    const base::Callback<void(const gfx::Image&)>& callback) {
+  callback.Run(image);
+}
+
+void ImageLoader::LoadExtensionIconDataURLAsync(
+    const extensions::Extension* extension,
+    int icon_size,
+    bool grayscale,
+    const base::Callback<void(const GURL&)>& callback) {
+  LoadExtensionIconAsync(extension,
+                         icon_size,
+                         grayscale,
+                         base::Bind(&ImageLoader::OnIconAvailable,
+                                    base::Unretained(this),
+                                    callback));
+}
+
+void ImageLoader::OnIconAvailable(
+    const base::Callback<void(const GURL&)>& callback,
+    const gfx::Image& image) {
+  content::BrowserThread::PostTask(
+      content::BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&ImageLoader::ConvertIconToURLOnFileThread,
+                 base::Unretained(this),
+                 image,
+                 callback));
+}
+
+void ImageLoader::ConvertIconToURLOnFileThread(
+    const gfx::Image& image,
+    const base::Callback<void(const GURL&)>& callback) {
+  GURL url = GetImageDataURL(image);
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI,
+      FROM_HERE,
+      base::Bind(&ImageLoader::OnIconConvertedToURL,
+                 base::Unretained(this),
+                 url,
+                 callback));
+}
+
+void ImageLoader::OnIconConvertedToURL(
+    const GURL& url,
+    const base::Callback<void(const GURL&)>& callback) {
+  callback.Run(url);
+}
+
+const SkBitmap* ImageLoader::GetDefaultAppImage() {
+  if (!default_app_data_.get())
+    default_app_data_.reset(GetImageByResourceId(IDR_APP_DEFAULT_ICON));
+
+  return default_app_data_.get();
+}
+
+const SkBitmap* ImageLoader::GetDefaultExtensionImage() {
+  if (!default_extension_data_.get()) {
+    default_extension_data_.reset(
+        GetImageByResourceId(IDR_EXTENSION_DEFAULT_ICON));
+  }
+
+  return default_extension_data_.get();
+}
+
 }  // namespace extensions