Prioritize smaller favicons over larger ones for tabs, etc.

chrome/browser/favicon/favicon_handler.h

Index: chrome/browser/favicon/favicon_handler.h
diff --git a/chrome/browser/favicon/favicon_handler.h b/chrome/browser/favicon/favicon_handler.h
index a59e944c42e6e66b7ba81b97b05851c1de1c8a01..bd3a73b25a45d7b0a00e39e42e0598e0c2061c4b 100644
--- a/chrome/browser/favicon/favicon_handler.h
+++ b/chrome/browser/favicon/favicon_handler.h
@@ -17,22 +17,19 @@
 #include "chrome/common/favicon_url.h"
 #include "chrome/common/ref_counted_util.h"
 #include "googleurl/src/gurl.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/favicon_size.h"
+#include "ui/gfx/image/image.h"
 
 class FaviconHandlerDelegate;
 class Profile;
 class RefCountedMemory;
-class SkBitmap;
 class TabContents;
 
 namespace content {
 class NavigationEntry;
 }
 
-namespace gfx {
-class Image;
-}
-
 // FaviconHandler works with FaviconTabHelper to fetch the specific type of
 // favicon.
 //
@@ -72,9 +69,11 @@ class Image;
 // db knew about the favicon), or requests the renderer to download the
 // favicon.
 //
-// When the renderer downloads the favicon SetFavicon is invoked,
-// at which point we update the favicon of the NavigationEntry and notify
-// the database to save the favicon.
+// When the renderer downloads favicons, it considers the entire list of
+// favicon candidates and chooses the one that best matches the preferred size
+// (or the first one if there is no preferred size). Once the matching favicon
+// has been determined, SetFavicon is called which updates the favicon of the
+// NavigationEntry and notifies the database to save the favicon.
 
 class FaviconHandler {
  public:
@@ -104,10 +103,14 @@ class FaviconHandler {
                     const FaviconTabHelper::ImageDownloadCallback& callback);
 
   // Message Handler.  Must be public, because also called from
-  // PrerenderContents.
+  // PrerenderContents. Collects the |image_urls| list.
   void OnUpdateFaviconURL(int32 page_id,
                           const std::vector<FaviconURL>& candidates);
 
+  // Processes the current image_irls_ entry, requesting the image from the
+  // history / download service.
+  void ProcessCurrentUrl();
+
   void OnDidDownloadFavicon(int id,
                             const GURL& image_url,
                             bool errored,
@@ -172,6 +175,23 @@ class FaviconHandler {
     history::IconType icon_type;
   };
 
+  struct FaviconCandidate {
+    FaviconCandidate();
+    ~FaviconCandidate();
+
+    FaviconCandidate(const GURL& url,
+                     const GURL& image_url,
+                     const gfx::Image& image,
+                     const SkBitmap& bitmap,
+                     history::IconType icon_type);
+
+    GURL url;
+    GURL image_url;
+    gfx::Image image;
+    SkBitmap bitmap;
+    history::IconType icon_type;
+  };
+
   // See description above class for details.
   void OnFaviconDataForInitialURL(FaviconService::Handle handle,
                                   history::FaviconData favicon);
@@ -195,11 +215,17 @@ class FaviconHandler {
                        history::IconType icon_type,
                        const FaviconTabHelper::ImageDownloadCallback& callback);
 
-  // Sets the image data for the favicon. This is invoked asynchronously after
-  // we request the TabContents to download the favicon.
+  // Updates |favicon_candidate_| and returns true if it is an exact match.
+  bool UpdateFaviconCandidate(const GURL& url,
+                              const GURL& image_url,
+                              const gfx::Image& image,
+                              history::IconType icon_type);
+
+  // Sets the image data for the favicon.
   void SetFavicon(const GURL& url,
                   const GURL& icon_url,
                   const gfx::Image& image,
+                  const SkBitmap& bitmap,
                   history::IconType icon_type);
 
   // Converts the FAVICON's image data to an SkBitmap and sets it on the
@@ -211,16 +237,15 @@ class FaviconHandler {
   void UpdateFavicon(content::NavigationEntry* entry, const gfx::Image* image);
 
   // If the image is not already at its preferred size, scales the image such
-  // that either the width and/or height is 16 pixels wide. Does nothing if the
-  // image is empty.
+  // that either the width and/or height == gfx::kFaviconSize. Does nothing if
+  // the image is empty.
   gfx::Image ResizeFaviconIfNeeded(const gfx::Image& image);
 
   void FetchFaviconInternal();
 
   // Return the current candidate if any.
   FaviconURL* current_candidate() {
-    return (urls_.size() > current_url_index_) ?
-        &urls_[current_url_index_] : NULL;
+    return (image_urls_.size() > 0) ? &image_urls_[0] : NULL;
   }
 
   // Returns the preferred_icon_size according icon_types_, 0 means no
@@ -253,10 +278,7 @@ class FaviconHandler {
   const int icon_types_;
 
   // The prioritized favicon candidates from the page back from the renderer.
-  std::vector<FaviconURL> urls_;
-
-  // The current candidate's index in urls_.
-  size_t current_url_index_;
+  std::deque<FaviconURL> image_urls_;
 
   // The FaviconData from history.
   history::FaviconData history_icon_;
@@ -267,6 +289,9 @@ class FaviconHandler {
   // This handler's delegate.
   FaviconHandlerDelegate* delegate_;  // weak
 
+  // Current favicon candidate.
+  FaviconCandidate favicon_candidate_;
+
   DISALLOW_COPY_AND_ASSIGN(FaviconHandler);
 };