Disable testharness.js timeout.

third_party/WebKit/LayoutTests/imported/wpt/resources/testharnessreport.js

Index: third_party/WebKit/LayoutTests/imported/wpt/resources/testharnessreport.js
diff --git a/third_party/WebKit/LayoutTests/imported/wpt/resources/testharnessreport.js b/third_party/WebKit/LayoutTests/imported/wpt/resources/testharnessreport.js
index 8bb7dea4d27f921d45cbbd6a01ab44c6030b0648..145a0c44d0c20bbc65dea70bf634752b3ba4c2a3 100644
--- a/third_party/WebKit/LayoutTests/imported/wpt/resources/testharnessreport.js
+++ b/third_party/WebKit/LayoutTests/imported/wpt/resources/testharnessreport.js
@@ -27,7 +27,13 @@
     // test results into an HTML table.  When that table is dumped as text, no
     // spacing between cells is preserved, and it is therefore not readable. By
     // setting output to false, the HTML table will not be created.
-    setup({"output":false});
+    // Also, disable timeout (except for explicit timeout), since the Blink
+    // layout test runner has its own timeout mechanism.
+    // See: https://github.com/w3c/testharness.js/blob/master/docs/api.md#setup
+    setup({
+        "output": false,
+        "explicit_timeout": true
+    });
 
     // Function used to convert the test status code into the corresponding
     // string