Clean up the IconLoader.

chrome/browser/icon_loader_auralinux.cc

Index: chrome/browser/icon_loader_auralinux.cc
diff --git a/chrome/browser/icon_loader_auralinux.cc b/chrome/browser/icon_loader_auralinux.cc
index 7783751e22209b52229242888ff873ff36782818..04818217269fe84e8589981293bc41b5f5a37b53 100644
--- a/chrome/browser/icon_loader_auralinux.cc
+++ b/chrome/browser/icon_loader_auralinux.cc
@@ -10,17 +10,12 @@
 #include "ui/views/linux_ui/linux_ui.h"
 
 // static
-IconGroupID IconLoader::ReadGroupIDFromFilepath(
+IconLoader::IconGroup IconLoader::GroupForFilepath(
     const base::FilePath& filepath) {
   return base::nix::GetFileMimeType(filepath);

[sky, 2016/10/24 15:56:25]

I believe this may trigger io:
std::string GetFileMimeType(const FilePath& filepath) {
  ...
  ThreadRestrictions::AssertIOAllowed();

AFAICT you call this from LookupIconFromFilepath, which I believe is meant to be
called from the main thread.

[Avi (use Gerrit), 2016/10/24 16:02:18]

:( Missed that platform. Let me try again.

 }
 
 // static
-bool IconLoader::IsIconMutableFromFilepath(const base::FilePath&) {
-  return false;
-}
-
-// static
 content::BrowserThread::ID IconLoader::ReadIconThreadID() {
   // ReadIcon() calls into views::LinuxUI and GTK2 code, so it must be on the UI
   // thread.