Catch uncaught promise rejections from V8 and log to console.

Source/core/dom/ExecutionContext.h

Index: Source/core/dom/ExecutionContext.h
diff --git a/Source/core/dom/ExecutionContext.h b/Source/core/dom/ExecutionContext.h
index 840698044bb057c3e1e084d9412daca69cffd064..d5da067710a525a78d3e68c639075a3b9e5e854e 100644
--- a/Source/core/dom/ExecutionContext.h
+++ b/Source/core/dom/ExecutionContext.h
@@ -85,7 +85,7 @@ public:
     KURL contextCompleteURL(const String& url) const { return virtualCompleteURL(url); }
 
     bool shouldSanitizeScriptError(const String& sourceURL, AccessControlStatus);
-    void reportException(PassRefPtrWillBeRawPtr<ErrorEvent>, int scriptId, PassRefPtrWillBeRawPtr<ScriptCallStack>, AccessControlStatus);
+    void reportException(PassRefPtrWillBeRawPtr<ErrorEvent>, int scriptId, PassRefPtrWillBeRawPtr<ScriptCallStack>, AccessControlStatus, bool isPromiseReject = false);
 
     virtual void addConsoleMessage(PassRefPtrWillBeRawPtr<ConsoleMessage>) = 0;
     virtual void logExceptionToConsole(const String& errorMessage, int scriptId, const String& sourceURL, int lineNumber, int columnNumber, PassRefPtrWillBeRawPtr<ScriptCallStack>) = 0;