Delay generation of User-Agent header to URLRequestHttpJob and accept custom User-Agent from XHR/Fe…

third_party/WebKit/LayoutTests/http/tests/inspector/extensions-headers.html

Index: third_party/WebKit/LayoutTests/http/tests/inspector/extensions-headers.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/inspector/extensions-headers.html b/third_party/WebKit/LayoutTests/http/tests/inspector/extensions-headers.html
index fd2f123e376bb888eb363946f3db7790ca7086cd..bb4e730b81f2f55dee16f61de533648b3eb2fa7f 100644
--- a/third_party/WebKit/LayoutTests/http/tests/inspector/extensions-headers.html
+++ b/third_party/WebKit/LayoutTests/http/tests/inspector/extensions-headers.html
@@ -23,12 +23,37 @@ function extension_testAddHeaders(nextTest)
 function doXHR()
 {
     var xhr = new XMLHttpRequest();
-    xhr.open("GET", "resources/echo-headers.php", false);
+    xhr.open("GET", "/resources/echo-headers.php", false);
     xhr.send(null);
     // Can't use output() here due to output order instability: this is invoked by inspectedWindow.eval(),
     // which is not serialized against output from extension, as the latter is posted asynchronously via
     // postMessage to front-end window.
-    document.getElementById("headers").textContent += xhr.responseText;
+    let xWebInspectorExtensionHeaderValue;
+    let httpUserAgentHeaderValue;
+    const lines = xhr.responseText.split('\n');
+    for (let line of lines) {
+        const parts = line.split(': ', 2);
+        if (parts.length < 2) {
+            continue;
+        }
+        const name = parts[0];
+        const value = parts[1];
+        if (name == "HTTP_X_WEBINSPECTOR_EXTENSION") {
+            xWebInspectorExtensionHeaderValue = value;
+        }
+        if (name == "HTTP_USER_AGENT") {
+            httpUserAgentHeaderValue = value;
+        }
+    }
+
+    let result = '';
+    if (xWebInspectorExtensionHeaderValue !== undefined) {
+        result += xWebInspectorExtensionHeaderValue + '\n';
+    }
+    if (httpUserAgentHeaderValue !== undefined) {
+        result += httpUserAgentHeaderValue + '\n';
+    }
+    document.getElementById("headers").textContent += result;
 }
 
 </script>