[Media Controls] Change cursor to pointer when hover button

Bug: 910382
Change-Id: Icf32ada34f569567deaa7917d82f79b35df9a8f9
Reviewed-on: https://chromium-review.googlesource.com/c/1357651Reviewed-by: Tommy Steimel <steimel@chromium.org>
Commit-Queue: Jazz Xu <jazzhsu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612942}

third_party/blink/renderer/modules/media_controls/resources/modernMediaControls.css

@@ -198,6 +198,7 @@ video::-internal-media-controls-picture-in-picture-button {
   border-width: 0;
   background-color: initial;
   color: inherit;
+  cursor: pointer;
 }
 
 video::-webkit-media-controls.sizing-small input[pseudo="-webkit-media-controls-play-button" i],
@@ -416,6 +417,7 @@ video::-webkit-media-controls-timeline {
   padding-right: 16px;
   margin: 0;
   background: transparent;
+  cursor: pointer;
   /* This prevents layout issues in quirks mode */
   box-sizing: unset !important;
 }
@@ -574,6 +576,7 @@ video::-webkit-media-controls-volume-slider {
   margin: 0;
   padding: 22px 0; /* (48px button panel height - 4px slider height) / 2  */
   background: transparent;
+  cursor: pointer;
   /* This prevents layout issues in quirks mode. */
   box-sizing: unset !important;
 }
@@ -678,6 +681,7 @@ video::-internal-media-controls-overflow-menu-list-item {
   line-height: 48px;
   padding-left: 16px;
   padding-right: 16px;
+  cursor: pointer;
 }
 
 video::-webkit-media-controls div[pseudo="-internal-media-controls-text-track-list" i].pip-presented,