diff --git a/atom/browser/net/atom_network_delegate.cc b/atom/browser/net/atom_network_delegate.cc
index 228cb5828e..4f9bc835ed 100644
--- a/atom/browser/net/atom_network_delegate.cc
+++ b/atom/browser/net/atom_network_delegate.cc
@@ -154,6 +154,7 @@ void ReadFromResponseObject(const base::DictionaryValue& response,
                             net::HttpRequestHeaders* headers) {
   const base::DictionaryValue* dict;
   if (response.GetDictionary("requestHeaders", &dict)) {
+    headers->Clear();
     for (base::DictionaryValue::Iterator it(*dict);
          !it.IsAtEnd();
          it.Advance()) {
diff --git a/spec/api-web-request-spec.coffee b/spec/api-web-request-spec.coffee
index a10ff3d127..5c78ef1d30 100644
--- a/spec/api-web-request-spec.coffee
+++ b/spec/api-web-request-spec.coffee
@@ -103,12 +103,23 @@ describe 'webRequest module', ->
           done()
         error: (xhr, errorType, error) -> done(errorType)
 
+    it 'resets the whole headers', (done) ->
+      requestHeaders = Test: 'header'
+      ses.webRequest.onBeforeSendHeaders (details, callback) ->
+        callback({requestHeaders})
+      ses.webRequest.onSendHeaders (details) ->
+        assert.deepEqual details.requestHeaders, requestHeaders
+        done()
+      $.ajax
+        url: defaultURL
+        error: (xhr, errorType, error) -> done(errorType)
+
   describe 'webRequest.onSendHeaders', ->
     afterEach ->
       ses.webRequest.onSendHeaders null
 
     it 'receives details object', (done) ->
-      ses.webRequest.onSendHeaders (details, callback) ->
+      ses.webRequest.onSendHeaders (details) ->
         assert.equal typeof details.requestHeaders, 'object'
       $.ajax
         url: defaultURL
diff --git a/spec/chromium-spec.coffee b/spec/chromium-spec.coffee
index d19933393f..cc28f2f7ad 100644
--- a/spec/chromium-spec.coffee
+++ b/spec/chromium-spec.coffee
@@ -85,7 +85,7 @@ describe 'chromium feature', ->
       w.loadURL url
 
   describe 'window.open', ->
-    @timeout 10000
+    @timeout 20000
 
     it 'returns a BrowserWindowProxy object', ->
       b = window.open 'about:blank', '', 'show=no'