Split up leak detector into two stages for better leak reporting.

third_party/WebKit/public/web/WebLeakDetector.h

Index: third_party/WebKit/public/web/WebLeakDetector.h
diff --git a/third_party/WebKit/public/web/WebLeakDetector.h b/third_party/WebKit/public/web/WebLeakDetector.h
index 4f65d92a85a78d6444d21c2e9b133783ecb8469c..1087f6126a43186194dfa8aec09003441a67307c 100644
--- a/third_party/WebKit/public/web/WebLeakDetector.h
+++ b/third_party/WebKit/public/web/WebLeakDetector.h
@@ -62,6 +62,12 @@ public:
     // Cleans up the DOM objects and counts them. |WebLeakDetectorClient::onLeakDetectionComplete()| is called when done.
     // This is supposed to be used for detecting DOM-object leaks.
     virtual void collectGarbageAndGetDOMCounts(WebLocalFrame*) = 0;
+
+    // Delay final round of garbage collections rounds, allowing instead
+    // the caller to manually start those using collectFinalGarbage().
+    virtual void delayFinalGarbageCollection() = 0;
+
+    virtual void collectFinalGarbage() = 0;
 };
 
 } // namespace blink