Make AppShimHostManager a RefCountedThreadSafe.

chrome/browser/browser_process_platform_part_mac.h

Index: chrome/browser/browser_process_platform_part_mac.h
diff --git a/chrome/browser/browser_process_platform_part_mac.h b/chrome/browser/browser_process_platform_part_mac.h
index 20d26454551aa2475d013b30dfe985954ffcf418..7f961309626b42dbbd3273bc68554db0855eec6c 100644
--- a/chrome/browser/browser_process_platform_part_mac.h
+++ b/chrome/browser/browser_process_platform_part_mac.h
@@ -5,12 +5,11 @@
 #ifndef CHROME_BROWSER_BROWSER_PROCESS_PLATFORM_PART_MAC_H_
 #define CHROME_BROWSER_BROWSER_PROCESS_PLATFORM_PART_MAC_H_
 
+#include "apps/app_shim/app_shim_host_manager_mac.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/browser_process_platform_part_base.h"
 
-class AppShimHostManager;
-
 namespace apps {
 class ExtensionAppShimHandler;
 }
@@ -29,7 +28,7 @@ class BrowserProcessPlatformPart : public BrowserProcessPlatformPartBase {
 
  private:
   // Hosts the IPC channel factory that App Shims connect to on Mac.
-  scoped_ptr<AppShimHostManager> app_shim_host_manager_;
+  scoped_refptr<AppShimHostManager> app_shim_host_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserProcessPlatformPart);
 };