Oilpan: Expose Heap::collectGarbage to the web layer

Heap::collectGarbage is needed in media_stream_impl_unittest.

BUG=340522

Review URL: https://codereview.chromium.org/543603003

git-svn-id: svn://svn.chromium.org/blink/trunk@181615 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/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

third_party/WebKit/public/web/WebHeap.h

@@ -47,6 +47,11 @@ public:
         BLINK_EXPORT SafePointScope();
         BLINK_EXPORT ~SafePointScope();
     };
+
+    // These APIs are only for testing purposes and should not be used
+    // outside of tests.
+    BLINK_EXPORT static void collectGarbageForTesting();
+    BLINK_EXPORT static void collectAllGarbageForTesting();
 };
 
 } // namespace blink