Oilpan: Expose Heap::collectGarbage to the web layer

Source/web/WebHeap.cpp

Index: Source/web/WebHeap.cpp
diff --git a/Source/web/WebHeap.cpp b/Source/web/WebHeap.cpp
index d814b2dca22a295a8c0fda0b5f7adc9fa63ac4d7..8445c7158839d36cfe50a34a4f8404efa7e69d2e 100644
--- a/Source/web/WebHeap.cpp
+++ b/Source/web/WebHeap.cpp
@@ -31,7 +31,7 @@
 #include "config.h"
 #include "public/web/WebHeap.h"
 
-#include "platform/heap/ThreadState.h"
+#include "platform/heap/Handle.h"
 
 namespace blink {
 
@@ -45,4 +45,14 @@ WebHeap::SafePointScope::~SafePointScope()
     ThreadState::current()->leaveSafePoint();
 }
 
+void WebHeap::collectGarbageForTesting()
+{
+    Heap::collectGarbage(ThreadState::HeapPointersOnStack);
+}
+
+void WebHeap::collectAllGarbageForTesting()
+{
+    Heap::collectAllGarbage();
+}
+
 } // namespace blink