Checks to enforce relative lifetimes for SdchManager.

net/base/sdch_manager.cc

Index: net/base/sdch_manager.cc
diff --git a/net/base/sdch_manager.cc b/net/base/sdch_manager.cc
index bcb5e32335bb07956d1e2532ecee20bf00877d02..34fc76af6ecd818a23340eaa90376892a310e8e5 100644
--- a/net/base/sdch_manager.cc
+++ b/net/base/sdch_manager.cc
@@ -243,7 +243,7 @@ void SdchManager::DictionarySet::AddDictionary(
   dictionaries_[server_hash] = dictionary;
 }
 
-SdchManager::SdchManager() {
+SdchManager::SdchManager() : factory_(this) {
   DCHECK(thread_checker_.CalledOnValidThread());
 }
 
@@ -620,6 +620,11 @@ SdchManager::CreateEmptyDictionarySetForTesting() {
   return scoped_ptr<DictionarySet>(new DictionarySet).Pass();
 }
 
+// For investigation of http://crbug.com/454198; remove when resolved.
+base::WeakPtr<SdchManager> SdchManager::GetWeakPtr() {
+  return factory_.GetWeakPtr();
+}
+
 // static
 void SdchManager::UrlSafeBase64Encode(const std::string& input,
                                       std::string* output) {