cros: Preload external extension icons.

chrome/browser/extensions/crx_installer.h

Index: chrome/browser/extensions/crx_installer.h
diff --git a/chrome/browser/extensions/crx_installer.h b/chrome/browser/extensions/crx_installer.h
index e9541dec8204defc135dbc6dfef30595eab22ef2..50859709e6b68811e4d2774e25245d21e71e8023 100644
--- a/chrome/browser/extensions/crx_installer.h
+++ b/chrome/browser/extensions/crx_installer.h
@@ -5,7 +5,10 @@
 #ifndef CHROME_BROWSER_EXTENSIONS_CRX_INSTALLER_H_
 #define CHROME_BROWSER_EXTENSIONS_CRX_INSTALLER_H_
 
+#include <map>
+#include <set>
 #include <string>
+#include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/file_path.h"
@@ -170,6 +173,8 @@ class CrxInstaller
     error_on_unsupported_requirements_ = val;
   }
 
+  void set_preload_sizes(const std::set<int>& sizes) { preload_sizes_ = sizes; }
+
   bool did_handle_successfully() const { return did_handle_successfully_; }
 
   Profile* profile() { return profile_; }
@@ -225,6 +230,12 @@ class CrxInstaller
   void ReportSuccessFromUIThread();
   void NotifyCrxInstallComplete(const Extension* extension);
 
+  // Runs on File thread. Preload icons if necessary.
+  void PreloadIcons();
+
+  // Runs on UI thread. Update extension icon cache with pre-loaded icons.
+  void CachePreloadedIcons();
+
   // The file we're installing.
   FilePath source_file_;
 
@@ -359,6 +370,12 @@ class CrxInstaller
 
   bool has_requirement_errors_;
 
+  // Sizes of the icons that need to be pre-loaded.
+  std::set<int> preload_sizes_;
+
+  // Maps requested preload icon size to loaded icons.
+  std::map<int, SkBitmap> preload_map_;
+
   DISALLOW_COPY_AND_ASSIGN(CrxInstaller);
 };