diff --git a/third_party/blink/web_tests/SlowTests b/third_party/blink/web_tests/SlowTests
index 6976a87603cb8..4ce2f815cbf63 100644
--- a/third_party/blink/web_tests/SlowTests
+++ b/third_party/blink/web_tests/SlowTests
@@ -564,7 +564,7 @@ crbug.com/1093849 external/wpt/dom/nodes/Element-classlist.html [ Slow ]
crbug.com/1093853 external/wpt/dom/ranges/Range-surroundContents.html [ Slow ]
crbug.com/1093478 external/wpt/quirks/unitless-length/limited-quirks.html [ Slow ]
crbug.com/1133836 external/wpt/scroll-to-text-fragment/redirects.html [ Slow ]
-crbug.com/1134580 http/tests/eye-dropper/color-picker-show-eye-dropper.html [ Slow ]
+crbug.com/1134580 http/tests/eye-dropper/color-picker-show-eye-dropper.php [ Slow ]
crbug.com/1145716 fast/forms/calendar-picker/datetimelocal-picker-open-to-focused-field.html [ Slow ]
# These began to hit timeouts when moving from Windows-10-15063 to Windows-10-18363
diff --git a/third_party/blink/web_tests/http/tests/eye-dropper/color-picker-show-eye-dropper.html b/third_party/blink/web_tests/http/tests/eye-dropper/color-picker-show-eye-dropper.php
similarity index 96%
rename from third_party/blink/web_tests/http/tests/eye-dropper/color-picker-show-eye-dropper.html
rename to third_party/blink/web_tests/http/tests/eye-dropper/color-picker-show-eye-dropper.php
index 711c920d66df3..6c525d365e05c 100644
--- a/third_party/blink/web_tests/http/tests/eye-dropper/color-picker-show-eye-dropper.html
+++ b/third_party/blink/web_tests/http/tests/eye-dropper/color-picker-show-eye-dropper.php
@@ -1,3 +1,6 @@
+
diff --git a/third_party/blink/web_tests/http/tests/forms/color-picker-keyboard-cross-domain.html b/third_party/blink/web_tests/http/tests/forms/color-picker-keyboard-cross-domain.php
similarity index 92%
rename from third_party/blink/web_tests/http/tests/forms/color-picker-keyboard-cross-domain.html
rename to third_party/blink/web_tests/http/tests/forms/color-picker-keyboard-cross-domain.php
index c9525215e6dce..05cc13635b86d 100644
--- a/third_party/blink/web_tests/http/tests/forms/color-picker-keyboard-cross-domain.html
+++ b/third_party/blink/web_tests/http/tests/forms/color-picker-keyboard-cross-domain.php
@@ -1,3 +1,6 @@
+
@@ -9,7 +12,7 @@
let t = async_test("Test input color popup's keyboard usability when inside cross-process iframe.");
let iframe = document.createElement("iframe");
- iframe.src = "http://localhost:8000/forms/resources/color-picker-keyboard-cross-domain-iframe.html";
+ iframe.src = "http://localhost:8000/forms/resources/color-picker-keyboard-cross-domain-iframe.php";
const runTest = t.step_func((event) => {
// The eventSender.keyDown() invocations in the iframe create extra window messages.
diff --git a/third_party/blink/web_tests/http/tests/forms/date-picker-keyboard-cross-domain.html b/third_party/blink/web_tests/http/tests/forms/date-picker-keyboard-cross-domain.php
similarity index 92%
rename from third_party/blink/web_tests/http/tests/forms/date-picker-keyboard-cross-domain.html
rename to third_party/blink/web_tests/http/tests/forms/date-picker-keyboard-cross-domain.php
index 311b66cbf24e8..4ac7c4fd02a6e 100644
--- a/third_party/blink/web_tests/http/tests/forms/date-picker-keyboard-cross-domain.html
+++ b/third_party/blink/web_tests/http/tests/forms/date-picker-keyboard-cross-domain.php
@@ -1,3 +1,6 @@
+
@@ -9,7 +12,7 @@
let t = async_test("Test input date popup's keyboard usability when inside cross-process iframe.");
let iframe = document.createElement("iframe");
- iframe.src = "http://localhost:8000/forms/resources/date-picker-keyboard-cross-domain-iframe.html";
+ iframe.src = "http://localhost:8000/forms/resources/date-picker-keyboard-cross-domain-iframe.php";
const runTest = t.step_func((event) => {
// The eventSender.keyDown() invocations in the iframe create extra window messages.
diff --git a/third_party/blink/web_tests/http/tests/forms/resources/color-picker-keyboard-cross-domain-iframe.html b/third_party/blink/web_tests/http/tests/forms/resources/color-picker-keyboard-cross-domain-iframe.php
similarity index 93%
rename from third_party/blink/web_tests/http/tests/forms/resources/color-picker-keyboard-cross-domain-iframe.html
rename to third_party/blink/web_tests/http/tests/forms/resources/color-picker-keyboard-cross-domain-iframe.php
index b4fd643755de1..df74505e7c9e7 100644
--- a/third_party/blink/web_tests/http/tests/forms/resources/color-picker-keyboard-cross-domain-iframe.html
+++ b/third_party/blink/web_tests/http/tests/forms/resources/color-picker-keyboard-cross-domain-iframe.php
@@ -1,3 +1,6 @@
+
diff --git a/third_party/blink/web_tests/http/tests/forms/resources/date-picker-keyboard-cross-domain-iframe.html b/third_party/blink/web_tests/http/tests/forms/resources/date-picker-keyboard-cross-domain-iframe.php
similarity index 93%
rename from third_party/blink/web_tests/http/tests/forms/resources/date-picker-keyboard-cross-domain-iframe.html
rename to third_party/blink/web_tests/http/tests/forms/resources/date-picker-keyboard-cross-domain-iframe.php
index 1aead577e3e52..f69e197184647 100644
--- a/third_party/blink/web_tests/http/tests/forms/resources/date-picker-keyboard-cross-domain-iframe.html
+++ b/third_party/blink/web_tests/http/tests/forms/resources/date-picker-keyboard-cross-domain-iframe.php
@@ -1,3 +1,6 @@
+