[HttpCache] Store some memcache info to memory dumps for debugging

base/trace_event/memory_infra_background_whitelist.cc

Index: base/trace_event/memory_infra_background_whitelist.cc
diff --git a/base/trace_event/memory_infra_background_whitelist.cc b/base/trace_event/memory_infra_background_whitelist.cc
index ae74322040f45043af0183f8fda5b32223910170..a31107ae995611ad244e19b122a77a125bc38a8b 100644
--- a/base/trace_event/memory_infra_background_whitelist.cc
+++ b/base/trace_event/memory_infra_background_whitelist.cc
@@ -71,6 +71,8 @@ const char* const kAllocatorDumpNameWhitelist[] = {
     "net/ssl_session_cache",
     "net/url_request_context_0x?",
     "net/url_request_context_0x?/http_cache",
+    "net/url_request_context_0x?/http_cache/memory_backend",
+    "net/url_request_context_0x?/http_cache/simple_backend",
     "net/url_request_context_0x?/http_network_session",
     "net/url_request_context_0x?/sdch_manager",
     "web_cache/Image_resources",