Reset the nesting level for setInterval after completion.

third_party/WebKit/Source/core/frame/DOMTimer.cpp

Index: third_party/WebKit/Source/core/frame/DOMTimer.cpp
diff --git a/third_party/WebKit/Source/core/frame/DOMTimer.cpp b/third_party/WebKit/Source/core/frame/DOMTimer.cpp
index e38ac74e6489aa12c3e4eb579ca5f997bd5976ab..b473d26bcd1ee414ace004b4c4ef82026609b651 100644
--- a/third_party/WebKit/Source/core/frame/DOMTimer.cpp
+++ b/third_party/WebKit/Source/core/frame/DOMTimer.cpp
@@ -157,8 +157,18 @@ void DOMTimer::fired() {
         augmentRepeatInterval(minimumInterval - repeatInterval());
     }
 
+    // Get ExecutionContext early as it might be cleared during
+    // action->execute().
+    ExecutionContext* executionContext = getExecutionContext();
+
     // No access to member variables after this point, it can delete the timer.
     m_action->execute(context);
+
+    if (!executionContext)
+      return;
+
+    executionContext->timers()->setTimerNestingLevel(0);
+
     return;
   }