First version of PerformanceObserver

Source/core/timing/Performance.idl

Index: Source/core/timing/Performance.idl
diff --git a/Source/core/timing/Performance.idl b/Source/core/timing/Performance.idl
index 6a8fab6b0030ec60e72d6f7d0230919d69f66bae..07cf38a88e5f0c48da8cc95b28a9e06a0699aa90 100644
--- a/Source/core/timing/Performance.idl
+++ b/Source/core/timing/Performance.idl
@@ -29,21 +29,37 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+// http://w3c.github.io/performance-timeline/#entryType/index.html#idl-def-PerformanceEntryType
+enum PerformanceEntryType {
+    "composite",
+    "mark",
+    "measure",
+    "navigation",
+    "render",
+    "resource",
+    "server"
+};
+
+// http://w3c.github.io/performance-timeline/#idl-def-PerformanceObserverCallback
+callback PerformanceObserverCallback = void (PerformanceObserverEntryList entries, PerformanceObserver observer);
+
 // https://w3c.github.io/hr-time/#the-performance-interface
 
 // TODO(philipj): This interface should be [Exposed=(Window,Worker)]. Doing that
 // would allow the WorkerPerformance interface to be merged into this.
 // TODO(philipj): None of the optional DOMString arguments in this interface
 // should have a default value.
-interface Performance : EventTarget {
+[
+  GarbageCollected
+] interface Performance : EventTarget {
     DOMHighResTimeStamp now();
 
     // Performance Timeline
     // https://w3c.github.io/performance-timeline/#the-performance-interface
     // TODO(philipj): getEntries() should take an optional FilterOptions argument.
     [MeasureAs=UnprefixedPerformanceTimeline] PerformanceEntryList getEntries();
-    [MeasureAs=UnprefixedPerformanceTimeline] PerformanceEntryList getEntriesByType(DOMString entryType);
-    [MeasureAs=UnprefixedPerformanceTimeline] PerformanceEntryList getEntriesByName(DOMString name, optional DOMString entryType = null);
+    [MeasureAs=UnprefixedPerformanceTimeline] PerformanceEntryList getEntriesByType(PerformanceEntryType entryType);
+    [MeasureAs=UnprefixedPerformanceTimeline] PerformanceEntryList getEntriesByName(DOMString name, optional PerformanceEntryType entryType = null);
 
     // Resource Timing
     // https://w3c.github.io/resource-timing/#extensions-performance-interface
@@ -75,6 +91,10 @@ interface Performance : EventTarget {
     [RuntimeEnabled=FrameTimingSupport, MeasureAs=PerformanceFrameTiming] void setFrameTimingBufferSize(unsigned long maxSize);
     [RuntimeEnabled=FrameTimingSupport] attribute EventHandler onframetimingbufferfull;
 
+    // Performance Observer
+    // http://w3c.github.io/performance-timeline/#extensions-to-the-performance-interface-1
+    [Custom, RuntimeEnabled=PerformanceObserverSupport] PerformanceObserver createPerformanceObserver(PerformanceObserverCallback callback);
+
     // TODO(philipj): There is no spec for the Memory Info API, see blink-dev:
     // https://groups.google.com/a/chromium.org/d/msg/blink-dev/g5YRCGpC9vs/b4OJz71NmPwJ
     [Measure] readonly attribute MemoryInfo memory;