Fix unit test memory leaks following blink r183043

content/child/indexed_db/indexed_db_dispatcher_unittest.cc

Index: content/child/indexed_db/indexed_db_dispatcher_unittest.cc
diff --git a/content/child/indexed_db/indexed_db_dispatcher_unittest.cc b/content/child/indexed_db/indexed_db_dispatcher_unittest.cc
index 75ebc64db9cffcf09955ed5c80490a98ce230e7a..33b98f25149388bac0dd14dea1b0f48e616e70ba 100644
--- a/content/child/indexed_db/indexed_db_dispatcher_unittest.cc
+++ b/content/child/indexed_db/indexed_db_dispatcher_unittest.cc
@@ -16,6 +16,7 @@
 #include "third_party/WebKit/public/platform/WebBlobInfo.h"
 #include "third_party/WebKit/public/platform/WebData.h"
 #include "third_party/WebKit/public/platform/WebIDBCallbacks.h"
+#include "third_party/WebKit/public/web/WebHeap.h"
 
 using blink::WebBlobInfo;
 using blink::WebData;
@@ -67,6 +68,10 @@ class IndexedDBDispatcherTest : public testing::Test {
         thread_safe_sender_(new ThreadSafeSender(message_loop_proxy_.get(),
                                                  sync_message_filter_.get())) {}
 
+  virtual void TearDown() override {
+    blink::WebHeap::collectAllGarbageForTesting();
+  }
+
  protected:
   scoped_refptr<base::MessageLoopProxy> message_loop_proxy_;
   scoped_refptr<IPC::SyncMessageFilter> sync_message_filter_;