Add support for subresource request loads in AppCache for the network service.

content/browser/appcache/appcache_host.h

Index: content/browser/appcache/appcache_host.h
diff --git a/content/browser/appcache/appcache_host.h b/content/browser/appcache/appcache_host.h
index 31c714b5be4ba898f56955402ec8a0fc99ee0ae6..16efa4cd1e45db5ab773e7e84a0fc3d383106a30 100644
--- a/content/browser/appcache/appcache_host.h
+++ b/content/browser/appcache/appcache_host.h
@@ -13,6 +13,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "content/browser/appcache/appcache_group.h"
 #include "content/browser/appcache/appcache_service_impl.h"
@@ -194,6 +195,9 @@ class CONTENT_EXPORT AppCacheHost
   void PrepareForTransfer();
   void CompleteTransfer(int host_id, AppCacheFrontend* frontend);
 
+  // Returns a weak pointer reference to the host.
+  base::WeakPtr<AppCacheHost> GetWeakPtr();
+
  private:
   friend class content::AppCacheHostTest;
   friend class content::AppCacheStorageImplTest;
@@ -353,6 +357,10 @@ class CONTENT_EXPORT AppCacheHost
   FRIEND_TEST_ALL_PREFIXES(content::AppCacheHostTest, SelectCacheTwice);
   FRIEND_TEST_ALL_PREFIXES(content::AppCacheTest, CleanupUnusedCache);
 
+  // The WeakPtrFactory below must occur last in the class definition so they
+  // get destroyed last.

[kinuko, 2017/07/03 06:34:15]

nit: this comment felt a bit confusing to me (two 'last' in different context),
maybe just remove (we have clang warning for this right?) or 'they get destroyed
last' -> 'weak pointers are invalidated before other members'?

[ananta, 2017/07/03 07:36:47]

Removed this comment. I checked other places in the code. We have a number of
them which don't have a comment. 

+  base::WeakPtrFactory<AppCacheHost> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(AppCacheHost);
 };