LibWeb: Return milliseconds from unsafe_shared_current_time()

This was incorrectly changed to returning seconds in fc5cab5, which
meant the time passed to the callbacks of requestAnimationFrame() was
wrong.

Tests/LibWeb/Text/expected/PerformanceObserver/PerformanceObserver_basic.txt

@@ -7,8 +7,8 @@ list instanceof PerformanceObserverEntryList: true
 allEntries instanceof Array: true
 allEntries.length === 3: true
 allEntries[0] === startMark: true
-allEntries[1] === endMark: true
-allEntries[2] === measureMark: true
+allEntries[1] === measureMark: true
+allEntries[2] === endMark: true
 markEntries instanceof Array: true
 markEntries.length === 2: true
 markEntries[0] === startMark: true

Tests/LibWeb/Text/input/PerformanceObserver/PerformanceObserver_basic.html

@@ -17,8 +17,8 @@
         printlnBuffered(`allEntries instanceof Array: ${allEntries instanceof Array}`);
         printlnBuffered(`allEntries.length === 3: ${allEntries.length === 3}`);
         printlnBuffered(`allEntries[0] === startMark: ${allEntries[0] === startMark}`);
-        printlnBuffered(`allEntries[1] === endMark: ${allEntries[1] === endMark}`);
-        printlnBuffered(`allEntries[2] === measureMark: ${allEntries[2] === measureMark}`);
+        printlnBuffered(`allEntries[1] === measureMark: ${allEntries[1] === measureMark}`);
+        printlnBuffered(`allEntries[2] === endMark: ${allEntries[2] === endMark}`);
 
         const markEntries = list.getEntriesByType("mark");
         printlnBuffered(`markEntries instanceof Array: ${markEntries instanceof Array}`);

Userland/Libraries/LibWeb/HighResolutionTime/TimeOrigin.cpp

@@ -55,7 +55,8 @@ DOMHighResTimeStamp coarsened_shared_current_time(bool cross_origin_isolated_cap
 DOMHighResTimeStamp unsafe_shared_current_time()
 {
     // The unsafe shared current time must return the current value of the shared monotonic clock.
-    return MonotonicTime::now().truncated_seconds();
+    // Note: This is in milliseconds (stored as a double).
+    return MonotonicTime::now().nanoseconds() / 1.0e6;
 }
 
 }