Make favicons for about:history and about:bookmarks switch from lodpi to hidpi when dragging browser

chrome/browser/ui/webui/favicon_source.h

Index: chrome/browser/ui/webui/favicon_source.h
diff --git a/chrome/browser/ui/webui/favicon_source.h b/chrome/browser/ui/webui/favicon_source.h
index 2ccc6d3e89bf6d64d5670e8814201a6ec200d689..244c6ed1272ce3d30d6aedb8609e4c73dce9e2ff 100644
--- a/chrome/browser/ui/webui/favicon_source.h
+++ b/chrome/browser/ui/webui/favicon_source.h
@@ -52,7 +52,6 @@ class FaviconSource : public ChromeURLDataManager::DataSource {
 
   Profile* profile_;
 
- private:
   // Defines the allowed pixel sizes for requested favicons.
   enum IconSize {
     SIZE_16,
@@ -64,19 +63,32 @@ class FaviconSource : public ChromeURLDataManager::DataSource {
   struct IconRequest {
     IconRequest()
       : request_id(0),
+        request_path(""),
         size_in_dip(gfx::kFaviconSize),
         scale_factor(ui::SCALE_FACTOR_NONE) {
     }
-    IconRequest(int id, int size, ui::ScaleFactor scale)
+    IconRequest(int id,
+                const std::string& path,
+                int size,
+                ui::ScaleFactor scale)
       : request_id(id),
+        request_path(path),
         size_in_dip(size),
         scale_factor(scale) {
     }
     int request_id;
+    std::string request_path;
     int size_in_dip;
     ui::ScaleFactor scale_factor;
   };
 
+  // Called when the favicon data is missing to perform additional checks to
+  // locate the resource.
+  // |request| contains information for the failed request.
+  // Returns true if the missing resource is found.
+  virtual bool HandleMissingResource(const IconRequest& request);
+
+ private:
   void Init(Profile* profile, IconType type);
 
   // Called when favicon data is available from the history backend.