Blink changes to record interest rects for http://w3c.github.io/frame-timing/

Source/core/frame/UseCounter.h

Index: Source/core/frame/UseCounter.h
diff --git a/Source/core/frame/UseCounter.h b/Source/core/frame/UseCounter.h
index 5faebe82761ad53aaa0ad539374aa30c85c52da1..82393d881ccc164a10dbf97146dc9045a093ae44 100644
--- a/Source/core/frame/UseCounter.h
+++ b/Source/core/frame/UseCounter.h
@@ -707,6 +707,8 @@ public:
         StoreBufferOverflow = 773,
         SlotsBufferOverflow = 774,
         ObjectObserve = 775,
+        UnprefixedPerformanceClearFrameTimings = 776,

[chrishtr, 2015/05/09 00:51:52]

Why have Unprefixed at the start?

[MikeB, 2015/05/11 23:10:51]

Because I saw 
        UnprefixedPerformanceTimeline = 65,
        UnprefixedUserTiming = 67,
etc.
Happy to not have the 'Unprefixed' part if it's unnecessary.
I can just consolidate it as PerformanceFrameTiming and not have a separate one
for clear* and set*buffersize too.

[chrishtr, 2015/05/11 23:46:43]

Looks like this is because PrefixedPerformanceTimeline used to be enum value 66
(try a code search to see remnants).
You can just remove Unprefixed, since this complication doesn't apply to you.

I agree that combining them into a single UseCounter for PerformanceFrameTiming
is better, since we just want to count the usage of the overall feature.

+        UnprefixedPerformanceSetFrameTimingBufferSize = 777,
 
         // Add new features immediately above this line. Don't change assigned
         // numbers of any item, and don't reuse removed slots.