Replace PruneAllButActive with PruneAllButVisible.

chrome/browser/prerender/prerender_browsertest.cc

Index: chrome/browser/prerender/prerender_browsertest.cc
diff --git a/chrome/browser/prerender/prerender_browsertest.cc b/chrome/browser/prerender/prerender_browsertest.cc
index 2c85c34017dc8b942079e478033d8fbde1f0f1fc..6bd9a54bcfe18fe176f0c81bebec30eccae116f4 100644
--- a/chrome/browser/prerender/prerender_browsertest.cc
+++ b/chrome/browser/prerender/prerender_browsertest.cc
@@ -1365,12 +1365,16 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderVisibility) {
   NavigateToDestURL();
 }
 
-// Checks that the visibility API works when the prerender is quickly opened
-// in a new tab before it stops loading.
-IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderVisibilityQuickSwitch) {
-  PrerenderTestURL("files/prerender/prerender_visibility_quick.html",
-                   FINAL_STATUS_USED, 0);
-  NavigateToDestURL();
+// Checks that the prerendering of a page is canceled correctly when it is
+// quickly opened in a new tab before it stops loading.
+IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderQuickSwitch) {
+  PrerenderTestURL("files/prerender/prerender_page.html",
+                   FINAL_STATUS_CANCELLED, 0);
+  // Post a task to cancel all the prerenders.
+  MessageLoop::current()->PostTask(

[cbentzel, 2013/05/28 18:39:17]

I'm confused. I thought what this would test the case of starting a prerender,
never committing the first navigation, and trying to swap it in (or at least
that is my interpretation of the comments). Do you have any tests for this case?

[Charlie Reis, 2013/05/28 23:22:00]

I thought that's what the FINAL_STATUS_CANCELLED line was doing, but I don't
really understand how all these helper functions in the prerender tests work.  I
was modeling this off the other tests that cancel a prerender, so I'm glad you
caught it.

What's the right way to validate that the prerender is not used when we try to
swap it in before the navigation commits?

+      FROM_HERE, base::Bind(&CancelAllPrerenders, GetPrerenderManager()));
+  content::RunMessageLoop();
+  EXPECT_TRUE(GetPrerenderContents() == NULL);
 }
 
 // Checks that the prerendering of a page is canceled correctly when a