Make `getComputedStyle` return the correct style for collapsed <img> elements.

third_party/WebKit/LayoutTests/http/tests/subresource_filter/image-disallowed.html

Index: third_party/WebKit/LayoutTests/http/tests/subresource_filter/image-disallowed.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/subresource_filter/image-disallowed.html b/third_party/WebKit/LayoutTests/http/tests/subresource_filter/image-disallowed.html
index 34bcfcb9c03184e8387effcd9857d1dabaaf0250..25460c8ffebb9944811e5cbd2f5061ccd0a33984 100644
--- a/third_party/WebKit/LayoutTests/http/tests/subresource_filter/image-disallowed.html
+++ b/third_party/WebKit/LayoutTests/http/tests/subresource_filter/image-disallowed.html
@@ -16,6 +16,8 @@ async_test(t => {
   i.onload = t.step_func_done(_ => {
     assert_equals(i.clientWidth, 100, "Images that are not disallowed should be displayed at their natural width.");
     assert_equals(i.clientHeight, 100, "Images that are not disallowed should be displayed at their natural height.");
+    let style = window.getComputedStyle(i);
+    assert_equals(style.display, "inline", "Images that are not disallowed should be display:inline");
   });
   i.onerror = t.unreached_func();
   i.src = "resources/alpha.png";
@@ -30,6 +32,8 @@ async_test(t => {
     assert_equals(i.clientHeight, 0, "Images that are disallowed should be collapsed.");
     assert_equals(i.naturalWidth, 0, "Images that are disallowed should not be loaded.");
     assert_equals(i.naturalHeight, 0, "Images that are disallowed should not be loaded.");
+    let style = window.getComputedStyle(i);
+    assert_equals(style.display, "none", "Images that are disallowed should be set to display:none");
   });
   i.src = "resources/beta.png";
   document.body.append(i);