Fix prerender histograms for multiple prerender case.

chrome/browser/prerender/prerender_manager_unittest.cc

Index: chrome/browser/prerender/prerender_manager_unittest.cc
diff --git a/chrome/browser/prerender/prerender_manager_unittest.cc b/chrome/browser/prerender/prerender_manager_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3b188f5d3c99d2a1a28c2a5d7602fbe5fc1e4843
--- /dev/null
+++ b/chrome/browser/prerender/prerender_manager_unittest.cc
@@ -0,0 +1,87 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/message_loop.h"
+#include "chrome/browser/prerender/prerender_manager.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "content/public/test/test_browser_thread.h"
+
+
+namespace prerender {
+
+namespace {
+
+// These tests don't require the dummy PrerenderContents & PrerenderManager that
+// the heavier PrerenderTest.* tests do.
+class PrerenderManagerTest : public testing::Test {
+ public:
+  PrerenderManagerTest()
+      : ui_thread_(content::BrowserThread::UI, &message_loop_),
+        prerender_manager_(NULL, NULL) {
+  }
+
+  PrerenderManager* prerender_manager() { return &prerender_manager_; }
+
+  MessageLoop message_loop_;
+  content::TestBrowserThread ui_thread_;
+  PrerenderManager prerender_manager_;
+};
+
+TEST_F(PrerenderManagerTest, IsWebContentsPrerenderedTest) {
+  // The methods being tested should not dereference their WebContents, instead
+  // they use it as a unique identifier.
+  int not_a_webcontents = 0;
+  content::WebContents* web_contents =
+      reinterpret_cast<content::WebContents*>(&not_a_webcontents);
+
+  EXPECT_FALSE(prerender_manager()->IsWebContentsPrerendered(
+      web_contents, NULL));
+
+  const Origin origin = ORIGIN_OMNIBOX;
+  prerender_manager()->MarkWebContentsAsPrerendered(web_contents, origin);
+
+  Origin test_origin = ORIGIN_NONE;
+  EXPECT_TRUE(prerender_manager()->IsWebContentsPrerendered(
+      web_contents, &test_origin));
+  EXPECT_EQ(origin, test_origin);

[mmenke, 2012/10/15 18:46:22]

Suggest another false case, after adding one WebContents, making sure another
one results false.  That still wouldn't have caught the bug, but it would have
caught an equivalent bug in the other loop.

[gavinp, 2012/10/16 13:52:01]

Done.

+
+  prerender_manager()->MarkWebContentsAsNotPrerendered(web_contents);
+  EXPECT_FALSE(prerender_manager()->IsWebContentsPrerendered(
+      web_contents, NULL));
+}
+
+TEST_F(PrerenderManagerTest, WouldWebContentsBePrerenderedTest) {
+  // The methods being tested should not dereference their WebContents, instead
+  // they use it as a unique identifier.
+  int not_a_webcontents = 0;
+  content::WebContents* web_contents =
+      reinterpret_cast<content::WebContents*>(&not_a_webcontents);
+
+  EXPECT_FALSE(prerender_manager()->WouldWebContentsBePrerendered(
+      web_contents, NULL));
+
+  const Origin origin = ORIGIN_OMNIBOX;
+  prerender_manager()->MarkWebContentsAsWouldBePrerendered(web_contents,
+                                                           origin);
+
+  Origin test_origin = ORIGIN_NONE;
+  EXPECT_TRUE(prerender_manager()->WouldWebContentsBePrerendered(
+      web_contents, &test_origin));
+  EXPECT_EQ(origin, test_origin);
+
+  // Control group (aka WouldBe...) web_contents need to be removed twice. See
+  // the comment in prerender_manager.cc at the definition of
+  // WouldBePrerenderedWebContentsData and its inner enum State.
+  prerender_manager()->MarkWebContentsAsNotPrerendered(web_contents);
+  EXPECT_TRUE(prerender_manager()->WouldWebContentsBePrerendered(
+      web_contents, NULL));
+
+  prerender_manager()->MarkWebContentsAsNotPrerendered(web_contents);
+  EXPECT_FALSE(prerender_manager()->WouldWebContentsBePrerendered(
+      web_contents, NULL));
+}
+
+}  // namespace
+
+}  // namespace prerender