Add DocumentTiming metrics for "time to first text paint"

public/web/WebPerformance.h

Index: public/web/WebPerformance.h
diff --git a/public/web/WebPerformance.h b/public/web/WebPerformance.h
index 5364356c5db4eb99b3d37b71a4ca4eea7d6e4064..a5ac3785d1ef4bb57132a931f32ed4e2988e8d9b 100644
--- a/public/web/WebPerformance.h
+++ b/public/web/WebPerformance.h
@@ -85,6 +85,8 @@ public:
     BLINK_EXPORT double loadEventStart() const;
     BLINK_EXPORT double loadEventEnd() const;
     BLINK_EXPORT double firstLayout() const;
+    BLINK_EXPORT double firstNonBlankText() const;
+    BLINK_EXPORT double firstCustomFontText() const;

[kinuko, 2015/09/14 14:14:33]

Um... some of these are from spec but others are not, for non-spec related ones
could we add comments somewhere, either on Performance or WebPerformance?

Esp. these two would be hard to distinguish without documentation.

[Kunihiko Sakamoto, 2015/09/15 05:11:01]

Added some comments in PerformanceTiming.h.

 
 #if BLINK_IMPLEMENTATION
     WebPerformance(const PassRefPtrWillBeRawPtr<Performance>&);