Fix flakiness when disabling swap out timer in tests.

content/browser/site_per_process_browsertest.cc

Index: content/browser/site_per_process_browsertest.cc
diff --git a/content/browser/site_per_process_browsertest.cc b/content/browser/site_per_process_browsertest.cc
index 978e63eaa65330e078a65d78ad489b8784c7d05b..2e15af5003b03501c2f2eb8fd6a045122662309a 100644
--- a/content/browser/site_per_process_browsertest.cc
+++ b/content/browser/site_per_process_browsertest.cc
@@ -4095,16 +4095,8 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,
 // delay the SwapOut ACK from the A->B navigation, so that the second B->A
 // navigation is initiated before the first page receives the SwapOut ACK.
 // Ensure that the RVH(A) that's pending deletion is not reused in that case.
-// crbug.com/554825
-#if defined(THREAD_SANITIZER)
-#define MAYBE_RenderViewHostPendingDeletionIsNotReused \
-        DISABLED_RenderViewHostPendingDeletionIsNotReused
-#else
-#define MAYBE_RenderViewHostPendingDeletionIsNotReused \
-        RenderViewHostPendingDeletionIsNotReused
-#endif
 IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,
-                       MAYBE_RenderViewHostPendingDeletionIsNotReused) {
+                       RenderViewHostPendingDeletionIsNotReused) {
   GURL a_url(embedded_test_server()->GetURL("a.com", "/title1.html"));
   NavigateToURL(shell(), a_url);
 
@@ -4121,6 +4113,7 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,
   // process.
   scoped_refptr<SwapoutACKMessageFilter> filter = new SwapoutACKMessageFilter();
   rfh->GetProcess()->AddFilter(filter.get());
+  rfh->DisableSwapOutTimerForTesting();
 
   // Navigate to B.  This must wait for DidCommitProvisionalLoad, as opposed to
   // DidStopLoading, since otherwise the SwapOut timer might call OnSwappedOut
@@ -4130,7 +4123,6 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,
   shell()->LoadURL(b_url);
   commit_observer.WaitForCommit();
   EXPECT_FALSE(deleted_observer.deleted());
-  rfh->ResetSwapOutTimerForTesting();
 
   // Since the SwapOut ACK for A->B is dropped, the first page's
   // RenderFrameHost and RenderViewHost should be pending deletion after the