Removing base::ThreadRestrictions::ScopedAllowIO from icon_manager_linux.cc

chrome/browser/icon_manager.h

Index: chrome/browser/icon_manager.h
diff --git a/chrome/browser/icon_manager.h b/chrome/browser/icon_manager.h
index 875c6d8ac15e770239a9d391d02fc0d0c34f7d42..60cabb0a591c8d6d1a6370d39e6fd355ea7ad746 100644
--- a/chrome/browser/icon_manager.h
+++ b/chrome/browser/icon_manager.h
@@ -47,14 +47,11 @@
 
 #include <map>
 
+#include "base/file_path.h"
 #include "chrome/browser/icon_loader.h"
 #include "chrome/common/cancelable_task_tracker.h"
 #include "ui/gfx/image/image.h"
 
-namespace base {
-class FilePath;
-}
-
 class IconManager : public IconLoader::Delegate {
  public:
   IconManager();
@@ -65,7 +62,8 @@ class IconManager : public IconLoader::Delegate {
   // it via 'LoadIcon'. The returned bitmap is owned by the IconManager and must
   // not be free'd by the caller. If the caller needs to modify the icon, it
   // must make a copy and modify the copy.
-  gfx::Image* LookupIcon(const base::FilePath& file_name, IconLoader::IconSize size);
+  gfx::Image* LookupIconFromFilepath(const base::FilePath& file_name,
+                                     IconLoader::IconSize size);
 
   typedef base::Callback<void(gfx::Image*)> IconRequestCallback;
 
@@ -89,16 +87,16 @@ class IconManager : public IconLoader::Delegate {
 
   // Get the identifying string for the given file. The implementation
   // is in icon_manager_[platform].cc.
-  static IconGroupID GetGroupIDFromFilepath(const base::FilePath& path);
+  static IconGroupID ReadGroupIDFromFilepath(const base::FilePath& path);
 
  private:
   struct CacheKey {
-    CacheKey(const IconGroupID& group, IconLoader::IconSize size);
+    CacheKey(const base::FilePath& file_name, IconLoader::IconSize size);

[Robert Sesek, 2013/02/11 20:52:23]

I think this change will result in many more cache misses, and therefore more
icon reading and icon storing. Clients likely won't look up the icon for the
same file multiple times, but may look up icons for the same kind of file.

Maybe the IconLoader::Delegate should be extended with a |gfx::Image*
CachedIconWithGroupID(const IconGroupID&)| method, which would involve a series
of message passes:

Client calls LoadIcon [UI thread] -> ReadGroup [FILE thread] -> Check Cache [UI]
-> Load Icon if Necessary [FILE] -> Run Callback [UI]

If that new delegate method returns non-NULL, the icon isn't loaded again and
the callback is just run with the cache result.

 
     // Used as a key in the map below, so we need this comparator.
     bool operator<(const CacheKey &other) const;
 
-    IconGroupID group;
+    base::FilePath file_name;
     IconLoader::IconSize size;
   };