Report first frame of animated image as LCP render time. (web-platfor…

…m-tests#49402)

Change-Id: If9df1402752265539fc82ae1b9ab356a7c1fceb3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6038997
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Ian Clelland <iclelland@chromium.org>
Reviewed-by: Annie Sullivan <sullivan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1388807}

Co-authored-by: Ian Clelland <iclelland@chromium.org>

largest-contentful-paint/animated/observe-cross-origin-animated-image.tentative.html

@@ -23,7 +23,7 @@
       const entry = await load_and_observe(url);
       // anim-gr.png is 100 by 50.
       const size = 100 * 50;
-      checkImage(entry, url, 'image_id', size, beforeLoad, ["renderTimeIs0", "animated-zero"]);
+      checkImage(entry, url, 'image_id', size, beforeLoad, ["animated"]);
     }, "Same origin animated image is observable and has a first frame.");
   </script>
 </body>

largest-contentful-paint/resources/largest-contentful-paint-helpers.js

@@ -40,8 +40,6 @@ function checkImage(entry, expectedUrl, expectedID, expectedSize, timeLowerBound
   if (options.includes('skip')) {
     return;
   }
-  assert_between_inclusive(entry.loadTime, timeLowerBound, entry.renderTime,
-    'loadTime should occur between the lower bound and the renderTime');
   assert_greater_than_equal(performance.now(), entry.renderTime,
     'renderTime should occur before the entry is dispatched to the observer.');
   assert_approx_equals(entry.startTime, entry.renderTime, 0.001,
@@ -55,14 +53,14 @@ function checkImage(entry, expectedUrl, expectedID, expectedSize, timeLowerBound
   }
 
   if (options.includes('animated')) {
-    assert_greater_than(entry.loadTime, entry.firstAnimatedFrameTime,
-      'firstAnimatedFrameTime should be smaller than loadTime');
-    assert_greater_than(entry.renderTime, entry.firstAnimatedFrameTime,
-      'firstAnimatedFrameTime should be smaller than renderTime');
-    assert_less_than(entry.firstAnimatedFrameTime, image_delay,
-      'firstAnimatedFrameTime should be smaller than the delay applied to the second frame');
-    assert_greater_than(entry.firstAnimatedFrameTime, 0,
-      'firstAnimatedFrameTime should be larger than 0');
+    assert_less_than(entry.renderTime, image_delay,
+      'renderTime should be smaller than the delay applied to the second frame');
+    assert_greater_than(entry.renderTime, 0,
+      'renderTime should be larger than 0');
+  }
+  else {
+    assert_between_inclusive(entry.loadTime, timeLowerBound, entry.renderTime,
+      'loadTime should occur between the lower bound and the renderTime');
   }
 }