BrowserThemePacks can do IO during shutdown, so delete them on the FILE thread.

BUG=61135
TEST=none

Review URL: http://codereview.chromium.org/4213005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@64478 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 11 insertions, 3 deletions

diff --git a/chrome/browser/themes/browser_theme_pack.h b/chrome/browser/themes/browser_theme_pack.h
index 85d27af..5fa55e2 100644
--- a/chrome/browser/themes/browser_theme_pack.h
+++ b/chrome/browser/themes/browser_theme_pack.h
@@ -13,6 +13,7 @@
 #include "base/scoped_ptr.h"
 #include "base/ref_counted.h"
 #include "gfx/color_utils.h"
+#include "chrome/browser/browser_thread.h"
 #include "chrome/common/extensions/extension.h"
 
 namespace base {
@@ -35,10 +36,13 @@ class RefCountedMemory;
 // UI thread that consumes a BrowserThemePack. There is no locking; thread
 // safety between the writing thread and the UI thread is ensured by having the
 // data be immutable.
-class BrowserThemePack : public base::RefCountedThreadSafe<BrowserThemePack> {
+//
+// BrowserThemePacks are always deleted on the file thread because in the
+// common case, they are backed by mmapped data and the unmmapping operation
+// will trip our IO on the UI thread detector.
+class BrowserThemePack : public base::RefCountedThreadSafe<
+    BrowserThemePack, BrowserThread::DeleteOnFileThread> {
  public:
-  ~BrowserThemePack();
-
   // Builds the theme pack from all data from |extension|. This is often done
   // on a separate thread as it takes so long. This can fail and return NULL in
   // the case where the theme has invalid data.
@@ -79,6 +83,8 @@ class BrowserThemePack : public base::RefCountedThreadSafe<BrowserThemePack> {
   bool HasCustomImage(int id) const;
 
  private:
+  friend struct BrowserThread::DeleteOnThread<BrowserThread::FILE>;
+  friend class DeleteTask<BrowserThemePack>;
   friend class BrowserThemePackTest;
 
   // Cached images. We cache all retrieved and generated bitmaps and keep
@@ -98,6 +104,8 @@ class BrowserThemePack : public base::RefCountedThreadSafe<BrowserThemePack> {
   // Default. Everything is empty.
   BrowserThemePack();
 
+  virtual ~BrowserThemePack();
+
   // Builds a header ready to write to disk.
   void BuildHeader(Extension* extension);