diff --git a/dom/bindings/BindingUtils.cpp b/dom/bindings/BindingUtils.cpp
index 83b1d7a66b37..2959af1f5a46 100644
--- a/dom/bindings/BindingUtils.cpp
+++ b/dom/bindings/BindingUtils.cpp
@@ -13,7 +13,6 @@
 #include "mozilla/FloatingPoint.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Preferences.h"
-#include "mozilla/unused.h"
 
 #include "AccessCheck.h"
 #include "jsfriendapi.h"
@@ -47,7 +46,6 @@
 #include "mozilla/jsipc/CrossProcessObjectWrappers.h"
 #include "WorkerPrivate.h"
 #include "nsDOMClassInfo.h"
-#include "ipc/ErrorIPCUtils.h"
 
 namespace mozilla {
 namespace dom {
@@ -151,31 +149,6 @@ ErrorResult::ThrowErrorWithMessage(va_list ap, const dom::ErrNum errorNumber,
   mMessage = message;
 }
 
-void
-ErrorResult::SerializeMessage(IPC::Message* aMsg) const
-{
-  using namespace IPC;
-  MOZ_ASSERT(mMessage);
-  WriteParam(aMsg, mMessage->mArgs);
-  WriteParam(aMsg, mMessage->mErrorNumber);
-}
-
-bool
-ErrorResult::DeserializeMessage(const IPC::Message* aMsg, void** aIter)
-{
-  using namespace IPC;
-  nsAutoPtr<Message> readMessage(new Message());
-  if (!ReadParam(aMsg, aIter, &readMessage->mArgs) ||
-      !ReadParam(aMsg, aIter, &readMessage->mErrorNumber)) {
-    return false;
-  }
-  if (mMessage) {
-    delete mMessage;
-  }
-  mMessage = readMessage.forget();
-  return true;
-}
-
 void
 ErrorResult::ThrowTypeError(const dom::ErrNum errorNumber, ...)
 {
@@ -328,37 +301,6 @@ ErrorResult::ReportNotEnoughArgsError(JSContext* cx,
   ThrowErrorMessage(cx, dom::MSG_MISSING_ARGUMENTS, errorMessage.get());
 }
 
-ErrorResult&
-ErrorResult::operator=(ErrorResult&& aRHS)
-{
-#ifdef DEBUG
-  mMightHaveUnreportedJSException = aRHS.mMightHaveUnreportedJSException;
-  aRHS.mMightHaveUnreportedJSException = false;
-#endif
-  if (aRHS.IsErrorWithMessage()) {
-    mMessage = aRHS.mMessage;
-    aRHS.mMessage = nullptr;
-  } else if (aRHS.IsJSException()) {
-    JSContext* cx = nsContentUtils::GetDefaultJSContextForThread();
-    MOZ_ASSERT(cx);
-    mJSException.setUndefined();
-    if (!js::AddRawValueRoot(cx, &mJSException, "ErrorResult::mJSException")) {
-      MOZ_CRASH("Could not root mJSException, we're about to OOM");
-    }
-    mJSException = aRHS.mJSException;
-    aRHS.mJSException.setUndefined();
-    js::RemoveRawValueRoot(cx, &aRHS.mJSException);
-  } else {
-    // Null out the union on both sides for hygiene purposes.
-    mMessage = aRHS.mMessage = nullptr;
-  }
-  // Note: It's important to do this last, since this affects the condition
-  // checks above!
-  mResult = aRHS.mResult;
-  aRHS.mResult = NS_OK;
-  return *this;
-}
-
 namespace dom {
 
 bool
diff --git a/dom/bindings/ErrorIPCUtils.h b/dom/bindings/ErrorIPCUtils.h
deleted file mode 100644
index c929949bc4b0..000000000000
--- a/dom/bindings/ErrorIPCUtils.h
+++ /dev/null
@@ -1,70 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
-/* vim: set ts=2 sw=2 et tw=79: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "ipc/IPCMessageUtils.h"
-#include "mozilla/ErrorResult.h"
-#include "mozilla/Assertions.h"
-#include "mozilla/Move.h"
-
-#ifndef IPC_ErrorIPCUtils_h
-#define IPC_ErrorIPCUtils_h
-
-namespace IPC {
-
-template<>
-struct ParamTraits<mozilla::dom::ErrNum> :
-  public ContiguousEnumSerializer<mozilla::dom::ErrNum,
-                                  mozilla::dom::ErrNum(0),
-                                  mozilla::dom::ErrNum(mozilla::dom::Err_Limit)> {};
-
-template<>
-struct ParamTraits<mozilla::ErrorResult>
-{
-  typedef mozilla::ErrorResult paramType;
-
-  static void Write(Message* aMsg, const paramType& aParam)
-  {
-    // It should be the case that mMightHaveUnreportedJSException can only be
-    // true when we're expecting a JS exception.  We cannot send such messages
-    // over the IPC channel since there is no sane way of transferring the JS
-    // value over to the other side.  Callers should never do that.
-    MOZ_ASSERT_IF(aParam.IsJSException(), aParam.mMightHaveUnreportedJSException);
-    if (aParam.IsJSException()
-#ifdef DEBUG
-        || aParam.mMightHaveUnreportedJSException
-#endif
-        ) {
-      MOZ_CRASH("Cannot encode an ErrorResult representing a Javascript exception");
-    }
-
-    WriteParam(aMsg, aParam.mResult);
-    WriteParam(aMsg, aParam.IsErrorWithMessage());
-    if (aParam.IsErrorWithMessage()) {
-      aParam.SerializeMessage(aMsg);
-    }
-  }
-
-  static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
-  {
-    paramType readValue;
-    if (!ReadParam(aMsg, aIter, &readValue.mResult)) {
-      return false;
-    }
-    bool hasMessage = false;
-    if (!ReadParam(aMsg, aIter, &hasMessage)) {
-      return false;
-    }
-    if (hasMessage && !readValue.DeserializeMessage(aMsg, aIter)) {
-      return false;
-    }
-    *aResult = Move(readValue);
-    return true;
-  }
-};
-
-}
-
-#endif
diff --git a/dom/bindings/ErrorResult.h b/dom/bindings/ErrorResult.h
index 9beb59a96893..64f977762b7a 100644
--- a/dom/bindings/ErrorResult.h
+++ b/dom/bindings/ErrorResult.h
@@ -17,12 +17,6 @@
 #include "nscore.h"
 #include "nsStringGlue.h"
 #include "mozilla/Assertions.h"
-#include "mozilla/Move.h"
-
-namespace IPC {
-class Message;
-template <typename> struct ParamTraits;
-}
 
 namespace mozilla {
 
@@ -62,12 +56,6 @@ public:
   }
 #endif
 
-  ErrorResult(ErrorResult&& aRHS)
-  {
-    *this = Move(aRHS);
-  }
-  ErrorResult& operator=(ErrorResult&& aRHS);
-
   void Throw(nsresult rv) {
     MOZ_ASSERT(NS_FAILED(rv), "Please don't try throwing success");
     MOZ_ASSERT(rv != NS_ERROR_TYPE_ERR, "Use ThrowTypeError()");
@@ -173,10 +161,6 @@ private:
     JS::Value mJSException; // valid when IsJSException()
   };
 
-  friend struct IPC::ParamTraits<ErrorResult>;
-  void SerializeMessage(IPC::Message* aMsg) const;
-  bool DeserializeMessage(const IPC::Message* aMsg, void** aIter);
-
 #ifdef DEBUG
   // Used to keep track of codepaths that might throw JS exceptions,
   // for assertion purposes.
@@ -186,7 +170,6 @@ private:
   // Not to be implemented, to make sure people always pass this by
   // reference, not by value.
   ErrorResult(const ErrorResult&) = delete;
-  void operator=(const ErrorResult&) = delete;
   void ThrowErrorWithMessage(va_list ap, const dom::ErrNum errorNumber,
                              nsresult errorType);
 };
diff --git a/dom/bindings/Errors.msg b/dom/bindings/Errors.msg
index 2b38a24bf14f..2c828efa1026 100644
--- a/dom/bindings/Errors.msg
+++ b/dom/bindings/Errors.msg
@@ -73,5 +73,4 @@ MSG_DEF(MSG_INVALID_RESPONSE_STATUSCODE_ERROR, 0, JSEXN_RANGEERR, "Invalid respo
 MSG_DEF(MSG_INVALID_REDIRECT_STATUSCODE_ERROR, 0, JSEXN_RANGEERR, "Invalid redirect status code.")
 MSG_DEF(MSG_INVALID_URL_SCHEME, 2, JSEXN_TYPEERR, "{0} URL {1} must be either http:// or https://.")
 MSG_DEF(MSG_RESPONSE_URL_IS_NULL, 0, JSEXN_TYPEERR, "Cannot set Response.finalURL when Response.url is null.")
-MSG_DEF(MSG_RESPONSE_HAS_VARY_STAR, 0, JSEXN_TYPEERR, "Invalid Response object with a 'Vary: *' header.")
 MSG_DEF(MSG_BAD_FORMDATA, 0, JSEXN_TYPEERR, "Could not parse content as FormData.")
diff --git a/dom/bindings/moz.build b/dom/bindings/moz.build
index 25f2ffb8359b..747fec2a7ee3 100644
--- a/dom/bindings/moz.build
+++ b/dom/bindings/moz.build
@@ -6,10 +6,6 @@
 
 TEST_DIRS += ['test']
 
-EXPORTS.ipc += [
-    'ErrorIPCUtils.h',
-]
-
 EXPORTS.mozilla += [
     'ErrorResult.h',
 ]
diff --git a/dom/cache/Cache.cpp b/dom/cache/Cache.cpp
index c01770515217..c0ba120ac996 100644
--- a/dom/cache/Cache.cpp
+++ b/dom/cache/Cache.cpp
@@ -452,16 +452,12 @@ Cache::RecvMatchAllResponse(RequestId aRequestId, nsresult aRv,
 }
 
 void
-Cache::RecvAddAllResponse(RequestId aRequestId,
-                          const mozilla::ErrorResult& aError)
+Cache::RecvAddAllResponse(RequestId aRequestId, nsresult aRv)
 {
   nsRefPtr<Promise> promise = RemoveRequestPromise(aRequestId);
 
-  if (aError.Failed()) {
-    // TODO: Remove this const_cast (bug 1152078).
-    // It is safe for now since this ErrorResult is handed off to us by IPDL
-    // and is thrown into the trash afterwards.
-    promise->MaybeReject(const_cast<ErrorResult&>(aError));
+  if (NS_FAILED(aRv)) {
+    promise->MaybeReject(aRv);
     return;
   }
 
diff --git a/dom/cache/Cache.h b/dom/cache/Cache.h
index ceae13efafa3..93a77f2d8109 100644
--- a/dom/cache/Cache.h
+++ b/dom/cache/Cache.h
@@ -81,8 +81,7 @@ public:
                          const PCacheResponseOrVoid& aResponse);
   void RecvMatchAllResponse(RequestId aRequestId, nsresult aRv,
                             const nsTArray<PCacheResponse>& aResponses);
-  void RecvAddAllResponse(RequestId aRequestId,
-                          const mozilla::ErrorResult& aError);
+  void RecvAddAllResponse(RequestId aRequestId, nsresult aRv);
   void RecvPutResponse(RequestId aRequestId, nsresult aRv);
 
   void RecvDeleteResponse(RequestId aRequestId, nsresult aRv,
diff --git a/dom/cache/CacheChild.cpp b/dom/cache/CacheChild.cpp
index 4facd1ebb77b..4adf3b71aece 100644
--- a/dom/cache/CacheChild.cpp
+++ b/dom/cache/CacheChild.cpp
@@ -146,13 +146,12 @@ CacheChild::RecvMatchAllResponse(const RequestId& requestId, const nsresult& aRv
 }
 
 bool
-CacheChild::RecvAddAllResponse(const RequestId& requestId,
-                               const mozilla::ErrorResult& aError)
+CacheChild::RecvAddAllResponse(const RequestId& requestId, const nsresult& aRv)
 {
   NS_ASSERT_OWNINGTHREAD(CacheChild);
   nsRefPtr<Cache> listener = mListener;
   if (listener) {
-    listener->RecvAddAllResponse(requestId, aError);
+    listener->RecvAddAllResponse(requestId, aRv);
   }
   return true;
 }
diff --git a/dom/cache/CacheChild.h b/dom/cache/CacheChild.h
index 58ca8ffb1297..d01f6f7352ba 100644
--- a/dom/cache/CacheChild.h
+++ b/dom/cache/CacheChild.h
@@ -55,7 +55,7 @@ private:
                        nsTArray<PCacheResponse>&& responses) override;
   virtual bool
   RecvAddAllResponse(const RequestId& requestId,
-                     const mozilla::ErrorResult& aError) override;
+                     const nsresult& aRv) override;
   virtual bool
   RecvPutResponse(const RequestId& aRequestId,
                   const nsresult& aRv) override;
diff --git a/dom/cache/CacheParent.cpp b/dom/cache/CacheParent.cpp
index c79da5d651e4..e98119447f62 100644
--- a/dom/cache/CacheParent.cpp
+++ b/dom/cache/CacheParent.cpp
@@ -23,7 +23,6 @@ namespace mozilla {
 namespace dom {
 namespace cache {
 
-using mozilla::dom::ErrNum;
 using mozilla::ipc::FileDescriptorSetParent;
 using mozilla::ipc::PFileDescriptorSetParent;
 
@@ -122,10 +121,7 @@ CacheParent::RecvAddAll(const RequestId& aRequestId,
                                  aRequests, requestStreams,
                                  getter_AddRefs(fetchPut));
   if (NS_WARN_IF(NS_FAILED(rv))) {
-    MOZ_ASSERT(rv != NS_ERROR_TYPE_ERR);
-    ErrorResult error;
-    error.Throw(rv);
-    if (!SendAddAllResponse(aRequestId, error)) {
+    if (!SendAddAllResponse(aRequestId, rv)) {
       // child process is gone, warn and allow actor to clean up normally
       NS_WARNING("Cache failed to send AddAll response.");
     }
@@ -260,7 +256,7 @@ CacheParent::OnCacheKeys(RequestId aRequestId, nsresult aRv,
 }
 
 void
-CacheParent::OnFetchPut(FetchPut* aFetchPut, RequestId aRequestId, const ErrorResult& aRv)
+CacheParent::OnFetchPut(FetchPut* aFetchPut, RequestId aRequestId, nsresult aRv)
 {
   aFetchPut->ClearListener();
   mFetchPutList.RemoveElement(aFetchPut);
diff --git a/dom/cache/CacheParent.h b/dom/cache/CacheParent.h
index 2aa757de6987..57d3ba5d9223 100644
--- a/dom/cache/CacheParent.h
+++ b/dom/cache/CacheParent.h
@@ -70,7 +70,7 @@ private:
 
   // FetchPut::Listener methods
   virtual void OnFetchPut(FetchPut* aFetchPut, RequestId aRequestId,
-                          const mozilla::ErrorResult& aRv) override;
+                          nsresult aRv) override;
 
   already_AddRefed<nsIInputStream>
   DeserializeCacheStream(const PCacheReadStreamOrVoid& aStreamOrVoid);
diff --git a/dom/cache/DBSchema.cpp b/dom/cache/DBSchema.cpp
index 2a8447896160..6c4f70b86e79 100644
--- a/dom/cache/DBSchema.cpp
+++ b/dom/cache/DBSchema.cpp
@@ -944,9 +944,9 @@ DBSchema::MatchByVaryHeader(mozIStorageConnection* aConn,
     for (; token;
          token = nsCRT::strtok(rawBuffer, NS_HTTP_HEADER_SEPS, &rawBuffer)) {
       nsDependentCString header(token);
-      MOZ_ASSERT(!header.EqualsLiteral("*"),
-                 "We should have already caught this in "
-                 "TypeUtils::ToPCacheResponseWithoutBody()");
+      if (header.EqualsLiteral("*")) {
+        continue;
+      }
 
       ErrorResult errorResult;
       nsAutoCString queryValue;
diff --git a/dom/cache/FetchPut.cpp b/dom/cache/FetchPut.cpp
index 3d41cf8e45d3..ef3248c78bcc 100644
--- a/dom/cache/FetchPut.cpp
+++ b/dom/cache/FetchPut.cpp
@@ -136,6 +136,7 @@ FetchPut::FetchPut(Listener* aListener, Manager* aManager,
   , mInitiatingThread(NS_GetCurrentThread())
   , mStateList(aRequests.Length())
   , mPendingCount(0)
+  , mResult(NS_OK)
 {
   MOZ_ASSERT(mListener);
   MOZ_ASSERT(mManager);
@@ -156,7 +157,6 @@ FetchPut::~FetchPut()
   MOZ_ASSERT(!mListener);
   mManager->RemoveListener(this);
   mManager->ReleaseCacheId(mCacheId);
-  mResult.ClearMessage(); // This may contain a TypeError.
 }
 
 nsresult
@@ -249,7 +249,7 @@ FetchPut::FetchComplete(FetchObserver* aObserver,
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-  if (aInternalResponse->IsError() && !mResult.Failed()) {
+  if (aInternalResponse->IsError() && NS_SUCCEEDED(mResult)) {
     MaybeSetError(NS_ERROR_FAILURE);
   }
 
@@ -259,10 +259,10 @@ FetchPut::FetchComplete(FetchObserver* aObserver,
       ToPCacheResponseWithoutBody(mStateList[i].mPCacheResponse,
                                   *aInternalResponse, rv);
       if (rv.Failed()) {
-        mResult = Move(rv);
-      } else {
-        aInternalResponse->GetBody(getter_AddRefs(mStateList[i].mResponseStream));
+        MaybeSetError(rv.ErrorCode());
+        return;
       }
+      aInternalResponse->GetBody(getter_AddRefs(mStateList[i].mResponseStream));
       mStateList[i].mFetchObserver = nullptr;
       MOZ_ASSERT(mPendingCount > 0);
       mPendingCount -= 1;
@@ -291,7 +291,7 @@ FetchPut::DoPutOnWorkerThread()
 {
   MOZ_ASSERT(mInitiatingThread == NS_GetCurrentThread());
 
-  if (mResult.Failed()) {
+  if (NS_FAILED(mResult)) {
     MaybeNotifyListener();
     return;
   }
@@ -377,9 +377,9 @@ FetchPut::MatchInPutList(const PCacheRequest& aRequest,
       for (; token;
            token = nsCRT::strtok(rawBuffer, NS_HTTP_HEADER_SEPS, &rawBuffer)) {
         nsDependentCString header(token);
-        MOZ_ASSERT(!header.EqualsLiteral("*"),
-                   "We should have already caught this in "
-                   "TypeUtils::ToPCacheResponseWithoutBody()");
+        if (header.EqualsLiteral("*")) {
+          continue;
+        }
 
         ErrorResult headerRv;
         nsAutoCString value;
@@ -428,10 +428,10 @@ FetchPut::OnCachePutAll(RequestId aRequestId, nsresult aRv)
 void
 FetchPut::MaybeSetError(nsresult aRv)
 {
-  if (mResult.Failed() || NS_SUCCEEDED(aRv)) {
+  if (NS_FAILED(mResult) || NS_SUCCEEDED(aRv)) {
     return;
   }
-  mResult.Throw(aRv);
+  mResult = aRv;
 }
 
 void
@@ -442,7 +442,6 @@ FetchPut::MaybeNotifyListener()
     return;
   }
   mListener->OnFetchPut(this, mRequestId, mResult);
-  mResult.ClearMessage(); // This may contain a TypeError.
 }
 
 nsIGlobalObject*
diff --git a/dom/cache/FetchPut.h b/dom/cache/FetchPut.h
index 4c1bad371d94..1efad6f6de27 100644
--- a/dom/cache/FetchPut.h
+++ b/dom/cache/FetchPut.h
@@ -9,7 +9,6 @@
 
 #include "mozilla/AlreadyAddRefed.h"
 #include "mozilla/Attributes.h"
-#include "mozilla/ErrorResult.h"
 #include "mozilla/dom/cache/Manager.h"
 #include "mozilla/dom/cache/PCacheTypes.h"
 #include "mozilla/dom/cache/Types.h"
@@ -40,7 +39,7 @@ public:
   {
   public:
     virtual void
-    OnFetchPut(FetchPut* aFetchPut, RequestId aRequestId, const ErrorResult& aRv) = 0;
+    OnFetchPut(FetchPut* aFetchPut, RequestId aRequestId, nsresult aRv) = 0;
   };
 
   static nsresult
@@ -105,7 +104,7 @@ private:
   nsCOMPtr<nsIThread> mInitiatingThread;
   nsTArray<State> mStateList;
   uint32_t mPendingCount;
-  ErrorResult mResult;
+  nsresult mResult;
   nsCOMPtr<nsIRunnable> mRunnable;
 
 public:
diff --git a/dom/cache/PCache.ipdl b/dom/cache/PCache.ipdl
index b10eb9bc4cbe..2ad5bf421e46 100644
--- a/dom/cache/PCache.ipdl
+++ b/dom/cache/PCache.ipdl
@@ -11,7 +11,6 @@ include protocol PBlob; // FIXME: bug 792908
 include protocol PCacheStreamControl;
 
 using mozilla::dom::cache::RequestId from "mozilla/dom/cache/Types.h";
-using mozilla::ErrorResult from "ipc/ErrorIPCUtils.h";
 include "mozilla/dom/cache/IPCUtils.h";
 
 namespace mozilla {
@@ -36,7 +35,7 @@ parent:
 child:
   MatchResponse(RequestId requestId, nsresult aRv, PCacheResponseOrVoid aResponse);
   MatchAllResponse(RequestId requestId, nsresult aRv, PCacheResponse[] responses);
-  AddAllResponse(RequestId requestId, ErrorResult aRv);
+  AddAllResponse(RequestId requestId, nsresult aRv);
   PutResponse(RequestId requestId, nsresult aRv);
   DeleteResponse(RequestId requestId, nsresult aRv, bool success);
   KeysResponse(RequestId requestId, nsresult aRv, PCacheRequest[] requests);
diff --git a/dom/cache/TypeUtils.cpp b/dom/cache/TypeUtils.cpp
index 9fd31ffcb1cf..d9fa6ff0c41b 100644
--- a/dom/cache/TypeUtils.cpp
+++ b/dom/cache/TypeUtils.cpp
@@ -26,8 +26,6 @@
 #include "nsStreamUtils.h"
 #include "nsString.h"
 #include "nsURLParsers.h"
-#include "nsCRT.h"
-#include "nsHttp.h"
 
 namespace {
 
@@ -106,29 +104,6 @@ ProcessURL(nsAString& aUrl, bool* aSchemeValidOut,
   *aUrlWithoutQueryOut = Substring(aUrl, 0, queryPos - 1);
 }
 
-static bool
-HasVaryStar(mozilla::dom::InternalHeaders* aHeaders)
-{
-  nsAutoTArray<nsCString, 16> varyHeaders;
-  ErrorResult rv;
-  aHeaders->GetAll(NS_LITERAL_CSTRING("vary"), varyHeaders, rv);
-  MOZ_ALWAYS_TRUE(!rv.Failed());
-
-  for (uint32_t i = 0; i < varyHeaders.Length(); ++i) {
-    nsAutoCString varyValue(varyHeaders[i]);
-    char* rawBuffer = varyValue.BeginWriting();
-    char* token = nsCRT::strtok(rawBuffer, NS_HTTP_HEADER_SEPS, &rawBuffer);
-    for (; token;
-         token = nsCRT::strtok(rawBuffer, NS_HTTP_HEADER_SEPS, &rawBuffer)) {
-      nsDependentCString header(token);
-      if (header.EqualsLiteral("*")) {
-        return true;
-      }
-    }
-  }
-  return false;
-}
-
 void
 SerializeNormalStream(nsIInputStream* aStream, PCacheReadStream& aReadStreamOut)
 {
@@ -291,10 +266,6 @@ TypeUtils::ToPCacheResponseWithoutBody(PCacheResponse& aOut,
   aOut.statusText() = aIn.GetStatusText();
   nsRefPtr<InternalHeaders> headers = aIn.UnfilteredHeaders();
   MOZ_ASSERT(headers);
-  if (HasVaryStar(headers)) {
-    aRv.ThrowTypeError(MSG_RESPONSE_HAS_VARY_STAR);
-    return;
-  }
   headers->GetPHeaders(aOut.headers());
   aOut.headersGuard() = headers->Guard();
   aOut.securityInfo() = aIn.GetSecurityInfo();
@@ -310,9 +281,6 @@ TypeUtils::ToPCacheResponse(PCacheResponse& aOut, Response& aIn, ErrorResult& aR
 
   nsRefPtr<InternalResponse> ir = aIn.GetInternalResponse();
   ToPCacheResponseWithoutBody(aOut, *ir, aRv);
-  if (NS_WARN_IF(aRv.Failed())) {
-    return;
-  }
 
   nsCOMPtr<nsIInputStream> stream;
   aIn.GetBody(getter_AddRefs(stream));
diff --git a/dom/cache/test/mochitest/test_cache_match_vary.js b/dom/cache/test/mochitest/test_cache_match_vary.js
index 9bb948b6a548..82f8c31738a2 100644
--- a/dom/cache/test/mochitest/test_cache_match_vary.js
+++ b/dom/cache/test/mochitest/test_cache_match_vary.js
@@ -107,59 +107,15 @@ function testBasicKeys() {
 }
 
 function testStar() {
-  function ensurePromiseRejected(promise) {
-    return promise
-      .then(function() {
-        ok(false, "Promise should be rejected");
-      }, function(err) {
-        is(err.name, "TypeError", "Attempting to store a Response with a Vary:* header must fail");
-      });
-  }
   var test;
-  return new Promise(function(resolve, reject) {
-    var cache;
-    caches.open(name).then(function(c) {
-      cache = c;
-      Promise.all([
-        ensurePromiseRejected(
-          cache.add(new Request(requestURL + "1", {headers: {"WhatToVary": "*"}}))),
-        ensurePromiseRejected(
-          cache.addAll([
-            new Request(requestURL + "2", {headers: {"WhatToVary": "*"}}),
-            requestURL + "3",
-          ])),
-        ensurePromiseRejected(
-          fetch(new Request(requestURL + "4", {headers: {"WhatToVary": "*"}}))
-            .then(function(response) {
-              return cache.put(requestURL + "4", response);
-            })),
-        ensurePromiseRejected(
-          cache.add(new Request(requestURL + "5", {headers: {"WhatToVary": "*,User-Agent"}}))),
-        ensurePromiseRejected(
-          cache.addAll([
-            new Request(requestURL + "6", {headers: {"WhatToVary": "*,User-Agent"}}),
-            requestURL + "7",
-          ])),
-        ensurePromiseRejected(
-          fetch(new Request(requestURL + "8", {headers: {"WhatToVary": "*,User-Agent"}}))
-            .then(function(response) {
-              return cache.put(requestURL + "8", response);
-            })),
-        ensurePromiseRejected(
-          cache.add(new Request(requestURL + "9", {headers: {"WhatToVary": "User-Agent,*"}}))),
-        ensurePromiseRejected(
-          cache.addAll([
-            new Request(requestURL + "10", {headers: {"WhatToVary": "User-Agent,*"}}),
-            requestURL + "10",
-          ])),
-        ensurePromiseRejected(
-          fetch(new Request(requestURL + "11", {headers: {"WhatToVary": "User-Agent,*"}}))
-            .then(function(response) {
-              return cache.put(requestURL + "11", response);
-            })),
-      ]).then(reject, resolve);
+  return setupTest({"WhatToVary": "*", "Cookie": "foo=bar"})
+    .then(function(t) {
+      test = t;
+      // Ensure that searching with a different Cookie header with Vary:* succeeds.
+      return test.cache.match(new Request(requestURL, {headers: {"Cookie": "bar=baz"}}));
+    }).then(function(r) {
+      return checkResponse(r, test.response, test.responseText);
     });
-  });
 }
 
 function testMatch() {
@@ -178,6 +134,23 @@ function testMatch() {
     });
 }
 
+function testStarAndAnotherHeader() {
+  var test;
+  return setupTest({"WhatToVary": "*,User-Agent"})
+    .then(function(t) {
+      test = t;
+      // Ensure that searching with a different User-Agent header fails.
+      return test.cache.match(new Request(requestURL, {headers: {"User-Agent": "MyUA"}}));
+    }).then(function(r) {
+      is(typeof r, "undefined", "Searching for a request with a non-matching User-Agent header should not succeed");
+      // Ensure that searching with a different User-Agent header but with ignoreVary succeeds.
+      return test.cache.match(new Request(requestURL, {headers: {"User-Agent": "MyUA"}}),
+                              {ignoreVary: true});
+    }).then(function(r) {
+      return checkResponse(r, test.response, test.responseText);
+    });
+}
+
 function testInvalidHeaderName() {
   var test;
   return setupTest({"WhatToVary": "Foo/Bar, User-Agent"})
@@ -312,8 +285,6 @@ function testMultipleCacheEntries() {
 function step(testPromise) {
   return testPromise.then(function() {
     caches.delete(name);
-  }, function() {
-    caches.delete(name);
   });
 }
 
@@ -323,6 +294,8 @@ step(testBasics()).then(function() {
   return step(testStar());
 }).then(function() {
   return step(testMatch());
+}).then(function() {
+  return step(testStarAndAnotherHeader());
 }).then(function() {
   return step(testInvalidHeaderName());
 }).then(function() {