Collect use counter for v8BreakIterator

Source/bindings/core/v8/V8PerIsolateData.cpp

Index: Source/bindings/core/v8/V8PerIsolateData.cpp
diff --git a/Source/bindings/core/v8/V8PerIsolateData.cpp b/Source/bindings/core/v8/V8PerIsolateData.cpp
index bfca715e18ab407bc1631c1be874600e8220e350..75e1dde0a9e159b5b7ff48c206c5fd0fb2ec0d14 100644
--- a/Source/bindings/core/v8/V8PerIsolateData.cpp
+++ b/Source/bindings/core/v8/V8PerIsolateData.cpp
@@ -56,10 +56,11 @@ static void useCounterCallback(v8::Isolate* isolate, v8::Isolate::UseCounterFeat
     case v8::Isolate::kUseAsm:
         UseCounter::count(currentExecutionContext(isolate), UseCounter::UseAsm);
         break;
+    case v8::Isolate::kBreakIterator:
+        UseCounter::count(currentExecutionContext(isolate), UseCounter::BreakIterator);

[haraken, 2014/10/14 11:01:41]

Are you sure that you want to use currentExecutionContext, not
callingExecutionContext? We normally use callingExecutionContext for
UseCounter::count.

(To be honest, I don't think the difference matters in most cases.)

[Erik Corry Chromium.org, 2014/10/14 11:21:00]

I'm doing the same as the kUseAsm counter does.  I'm not sure what the
difference is?

[marja, 2014/10/14 11:23:20]

haraken@: ultimately both get associated to the FrameHost (we use the Context to
get the Document and get the FrameHost from it); is it possible that they'd get
associated to different FrameHosts?

[haraken, 2014/10/14 11:29:43]

If the current execution context is a document of an iframe and the calling
execution context is a document of the iframe's parent frame, it's possible that
the FrameHosts differ. The question is for which document we want to count
UseCounters. We normally count UseCounters for the parent frame, and thus we
normally use callingExecutionContext().

So I think these two end up with different results, but I'm not sure if the
difference matters. If you don't have a strong reason to use
currentExecutionContext(), I'd prefer using callingExecutionContext() in both
kUseAsm and kBreakIterator for consistency.

+        break;
     default:
-        // V8 may be a newer version that has some use counters we don't know
-        // about yet. FIXME: Add support for v8::Isolate::kBreakIterator and
-        // UseCounter::BreakIterator.
+        ASSERT_NOT_REACHED();
         break;
     }
 }