Remove buffering from PerformanceLongTaskTiming as it's not in the spec.

third_party/WebKit/Source/core/timing/Performance.idl

Index: third_party/WebKit/Source/core/timing/Performance.idl
diff --git a/third_party/WebKit/Source/core/timing/Performance.idl b/third_party/WebKit/Source/core/timing/Performance.idl
index 00d9187f355bcb84d5e8691e3a5e7b0d09413855..d5f344735f4cbf5c9f7fd7a30141c18b8d410a16 100644
--- a/third_party/WebKit/Source/core/timing/Performance.idl
+++ b/third_party/WebKit/Source/core/timing/Performance.idl
@@ -75,11 +75,6 @@ interface Performance : EventTarget {
     [RuntimeEnabled=FrameTimingSupport, MeasureAs=PerformanceFrameTiming] void setFrameTimingBufferSize(unsigned long maxSize);
     [RuntimeEnabled=FrameTimingSupport] attribute EventHandler onframetimingbufferfull;
 
-    // Long Task Timing
-    [RuntimeEnabled=LongTaskObserver] void clearLongTaskTimings();
-    [RuntimeEnabled=LongTaskObserver] void setLongTaskTimingBufferSize(unsigned long maxSize);
-    [RuntimeEnabled=LongTaskObserver] attribute EventHandler onlongtasktimingbufferfull;
-
     // TODO(foolip): 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;