[dialog] Measure show/showModal.

As above.

Change-Id: Ibd1f4a342454960d211776568a73fa3bf8a8f8fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2522406
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Reviewed-by: Mason Freed <masonfreed@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824873}

third_party/blink/public/mojom/web_feature/web_feature.mojom

@@ -3051,6 +3051,8 @@ enum WebFeature {
   kV8HTMLVideoElement_GetVideoPlaybackQuality_Method = 3722,
   kXRWebGLBindingGetReflectionCubeMap = 3723,
   kXRFrameGetLightEstimate = 3724,
+  kV8HTMLDialogElement_Show_Method = 3725,
+  kV8HTMLDialogElement_ShowModal_Method = 3726,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.

third_party/blink/renderer/core/html/html_dialog_element.idl

@@ -30,7 +30,7 @@
 ] interface HTMLDialogElement : HTMLElement {
     [CEReactions, Reflect] attribute boolean open;
     attribute DOMString returnValue;
-    [CEReactions] void show();
-    [CEReactions, RaisesException] void showModal();
+    [CEReactions, Measure] void show();
+    [CEReactions, Measure, RaisesException] void showModal();
     [CEReactions] void close(optional DOMString returnValue);
 };

tools/metrics/histograms/enums.xml

@@ -30172,6 +30172,8 @@ Called by update_use_counter_feature_enum.py.-->
   <int value="3722" label="V8HTMLVideoElement_GetVideoPlaybackQuality_Method"/>
   <int value="3723" label="XRWebGLBindingGetReflectionCubeMap"/>
   <int value="3724" label="XRFrameGetLightEstimate"/>
+  <int value="3725" label="V8HTMLDialogElement_Show_Method"/>
+  <int value="3726" label="V8HTMLDialogElement_ShowModal_Method"/>
 </enum>
 
 <enum name="FeaturePolicyAllowlistType">