Honor User-Agent header added by WebCore

- do not strip User-Agent while flattening headers in renderer
- do not override User-Agent header in the network stack if one is already supplied by higher level;
- added RequestHeaders::SetHeaderIfMissing

TEST=URLRequestTestHTTP.OverrideUserAgent
BUG=http://crbug.com/67063
Review URL=http://codereview.chromium.org/6065008


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72131 0039d316-1c4b-4281-b951-d872f2087c98

net/http/http_request_headers.cc

@@ -76,6 +76,13 @@ void HttpRequestHeaders::Clear() {
   headers_.clear();
 }
 
+void HttpRequestHeaders::SetHeaderIfMissing(const base::StringPiece& key,
+                                            const base::StringPiece& value) {
+  HeaderVector::iterator it = FindHeader(key);
+  if (it == headers_.end())
+    headers_.push_back(HeaderKeyValuePair(key.as_string(), value.as_string()));
+}
+
 void HttpRequestHeaders::SetHeader(const base::StringPiece& key,
                                    const base::StringPiece& value) {
   HeaderVector::iterator it = FindHeader(key);

net/http/http_request_headers.h

@@ -95,6 +95,12 @@ class HttpRequestHeaders {
   // in the vector remains the same.  When comparing |key|, case is ignored.
   void SetHeader(const base::StringPiece& key, const base::StringPiece& value);
 
+  // Sets the header value pair for |key| and |value|, if |key| does not exist.
+  // If |key| already exists, the call is a no-op.
+  // When comparing |key|, case is ignored.
+  void SetHeaderIfMissing(const base::StringPiece& key,
+                          const base::StringPiece& value);
+
   // Removes the first header that matches (case insensitive) |key|.
   void RemoveHeader(const base::StringPiece& key);
 

net/http/http_request_headers_unittest.cc

@@ -67,6 +67,14 @@ TEST(HttpRequestHeaders, SetEmptyHeader) {
   EXPECT_EQ("Foo: Bar\r\nBar:\r\n\r\n", headers.ToString());
 }
 
+TEST(HttpRequestHeaders, SetHeaderIfMissing) {
+  HttpRequestHeaders headers;
+  headers.SetHeaderIfMissing("Foo", "Bar");
+  EXPECT_EQ("Foo: Bar\r\n\r\n", headers.ToString());
+  headers.SetHeaderIfMissing("Foo", "Baz");
+  EXPECT_EQ("Foo: Bar\r\n\r\n", headers.ToString());
+}
+
 TEST(HttpRequestHeaders, RemoveHeader) {
   HttpRequestHeaders headers;
   headers.SetHeader("Foo", "bar");

net/url_request/url_request_http_job.cc

@@ -303,18 +303,12 @@ void URLRequestHttpJob::AddExtraHeaders() {
   if (context) {
     // Only add default Accept-Language and Accept-Charset if the request
     // didn't have them specified.
-    if (!request_info_.extra_headers.HasHeader(
-        HttpRequestHeaders::kAcceptLanguage)) {
-      request_info_.extra_headers.SetHeader(
-          HttpRequestHeaders::kAcceptLanguage,
-          context->accept_language());
-    }
-    if (!request_info_.extra_headers.HasHeader(
-        HttpRequestHeaders::kAcceptCharset)) {
-      request_info_.extra_headers.SetHeader(
-          HttpRequestHeaders::kAcceptCharset,
-          context->accept_charset());
-    }
+    request_info_.extra_headers.SetHeaderIfMissing(
+        HttpRequestHeaders::kAcceptLanguage,
+        context->accept_language());
+    request_info_.extra_headers.SetHeaderIfMissing(
+        HttpRequestHeaders::kAcceptCharset,
+        context->accept_charset());
   }
 }
 
@@ -660,7 +654,7 @@ void URLRequestHttpJob::Start() {
   request_info_.priority = request_->priority();
 
   if (request_->context()) {
-    request_info_.extra_headers.SetHeader(
+    request_info_.extra_headers.SetHeaderIfMissing(
         HttpRequestHeaders::kUserAgent,
         request_->context()->GetUserAgent(request_->url()));
   }

net/url_request/url_request_unittest.cc

@@ -2642,3 +2642,32 @@ TEST_F(URLRequestTestHTTP, OverrideAcceptCharset) {
   MessageLoop::current()->Run();
   EXPECT_EQ(std::string("koi-8r"), d.data_received());
 }
+
+// Check that default User-Agent header is sent.
+TEST_F(URLRequestTestHTTP, DefaultUserAgent) {
+  ASSERT_TRUE(test_server_.Start());
+
+  TestDelegate d;
+  TestURLRequest req(test_server_.GetURL("echoheader?User-Agent"), &d);
+  req.set_context(new TestURLRequestContext());
+  req.Start();
+  MessageLoop::current()->Run();
+  EXPECT_EQ(req.context()->GetUserAgent(req.url()), d.data_received());
+}
+
+// Check that if request overrides the User-Agent header,
+// the default is not appended.
+TEST_F(URLRequestTestHTTP, OverrideUserAgent) {
+  ASSERT_TRUE(test_server_.Start());
+
+  TestDelegate d;
+  TestURLRequest
+      req(test_server_.GetURL("echoheaderoverride?User-Agent"), &d);
+  req.set_context(new TestURLRequestContext());
+  net::HttpRequestHeaders headers;
+  headers.SetHeader(net::HttpRequestHeaders::kUserAgent, "Lynx (textmode)");
+  req.SetExtraRequestHeaders(headers);
+  req.Start();
+  MessageLoop::current()->Run();
+  EXPECT_EQ(std::string("Lynx (textmode)"), d.data_received());
+}

webkit/glue/weburlloader_impl.cc

@@ -69,10 +69,8 @@ class HeaderFlattener : public WebHTTPHeaderVisitor {
     const std::string& value_utf8 = value.utf8();
 
     // Skip over referrer headers found in the header map because we already
-    // pulled it out as a separate parameter.  We likewise prune the UA since
-    // that will be added back by the network layer.
-    if (LowerCaseEqualsASCII(name_utf8, "referer") ||
-        LowerCaseEqualsASCII(name_utf8, "user-agent"))
+    // pulled it out as a separate parameter.
+    if (LowerCaseEqualsASCII(name_utf8, "referer"))
       return;
 
     // Skip over "Cache-Control: max-age=0" header if the corresponding