Tadeu Zagallo 080d3b9f62 [ReactNative] Add PerformanceLogger to measure TTI ...

Summary:
@public

Add PerformanceLogger to keep track of JS download, initial script execution and
full TTI.

Test Plan:
The Native side currently calls `addTimespans` when it's finish initializing
with the six values (start and end for the three events), so I just checked it
with a `PerformanceLogger.logTimespans()` at the end of the function.

```
2015-06-18 16:47:19.096 [info][tid:com.facebook.React.JavaScript] "ScriptDownload: 48ms"
2015-06-18 16:47:19.096 [info][tid:com.facebook.React.JavaScript] "ScriptExecution: 106ms"
2015-06-18 16:47:19.096 [info][tid:com.facebook.React.JavaScript] "TTI: 293ms"
```

2015-06-19 15:01:35 -08:00

..

RCTContextExecutor.h

[ReactNative] Make so each RCTContextExecutor has its own thread

2015-04-27 03:46:27 -08:00

RCTContextExecutor.m

[ReactNative] Add PerformanceLogger to measure TTI

2015-06-19 15:01:35 -08:00

RCTWebViewExecutor.h

Removed debug code from release builds

2015-04-21 09:47:21 -08:00

RCTWebViewExecutor.m

Increased warning levels to -Wall -Wextra, and fixed Xcode 7 beta issues

2015-06-15 07:52:50 -08:00