WebContentsObserver::RenderFrameCreated should be called for every RenderFrameHost.

content/browser/frame_host/render_frame_host_manager_unittest.cc

Index: content/browser/frame_host/render_frame_host_manager_unittest.cc
diff --git a/content/browser/frame_host/render_frame_host_manager_unittest.cc b/content/browser/frame_host/render_frame_host_manager_unittest.cc
index 798ab6a4ecf9b918db0c00b4b1da49195e966022..a5100dfbe4b2dc071a52f2e80d9c8271e3b260c9 100644
--- a/content/browser/frame_host/render_frame_host_manager_unittest.cc
+++ b/content/browser/frame_host/render_frame_host_manager_unittest.cc
@@ -124,8 +124,7 @@ class RenderViewHostDeletedObserver : public WebContentsObserver {
   DISALLOW_COPY_AND_ASSIGN(RenderViewHostDeletedObserver);
 };
 
-
-// This observer keeps track of the last deleted RenderViewHost to avoid
+// This observer keeps track of the last deleted RenderFrameHost to avoid
 // accessing it and causing use-after-free condition.
 class RenderFrameHostDeletedObserver : public WebContentsObserver {
  public:
@@ -193,6 +192,60 @@ class PluginFaviconMessageObserver : public WebContentsObserver {
   DISALLOW_COPY_AND_ASSIGN(PluginFaviconMessageObserver);
 };
 
+// Ensures that RenderFrameDeleted and RenderFrameCreated are called in a
+// consistent manner.
+class FrameLifetimeConsistencyChecker : public WebContentsObserver {
+ public:
+  explicit FrameLifetimeConsistencyChecker(WebContentsImpl* web_contents)
+      : WebContentsObserver(web_contents) {
+    RenderViewCreated(web_contents->GetRenderViewHost());
+    RenderFrameCreated(web_contents->GetMainFrame());
+  }
+
+  virtual void RenderFrameCreated(RenderFrameHost* render_frame_host) OVERRIDE {
+    std::pair<int, int> routing_pair =
+        std::make_pair(render_frame_host->GetProcess()->GetID(),
+                       render_frame_host->GetRoutingID());
+    bool was_live_already = !live_routes_.insert(routing_pair).second;
+    bool was_used_before = deleted_routes_.count(routing_pair) != 0;
+
+    if (was_live_already) {
+      FAIL() << "RenderFrameCreated called more than once for routing pair: "
+             << Format(render_frame_host);
+    } else if (was_used_before) {
+      FAIL() << "RenderFrameCreated called for routing pair "
+             << Format(render_frame_host) << " that was previously deleted.";
+    }
+  }
+
+  virtual void RenderFrameDeleted(RenderFrameHost* render_frame_host) OVERRIDE {
+    std::pair<int, int> routing_pair =
+        std::make_pair(render_frame_host->GetProcess()->GetID(),
+                       render_frame_host->GetRoutingID());
+    bool was_live = live_routes_.erase(routing_pair);
+    bool was_dead_already = !deleted_routes_.insert(routing_pair).second;
+
+    if (was_dead_already) {
+      FAIL() << "RenderFrameDeleted called more than once for routing pair "
+             << Format(render_frame_host);
+    } else if (!was_live) {
+      FAIL() << "RenderFrameDeleted called for routing pair "
+             << Format(render_frame_host)
+             << " for which RenderFrameCreated was never called";
+    }
+  }
+
+ private:
+  std::string Format(RenderFrameHost* render_frame_host) {
+    return base::StringPrintf(
+        "(%d, %d -> %s )",
+        render_frame_host->GetProcess()->GetID(),
+        render_frame_host->GetRoutingID(),
+        render_frame_host->GetSiteInstance()->GetSiteURL().spec().c_str());
+  }
+  std::set<std::pair<int, int> > live_routes_;
+  std::set<std::pair<int, int> > deleted_routes_;
+};
 
 }  // namespace
 
@@ -202,9 +255,11 @@ class RenderFrameHostManagerTest
   virtual void SetUp() OVERRIDE {
     RenderViewHostImplTestHarness::SetUp();
     WebUIControllerFactory::RegisterFactory(&factory_);
+    lifetime_checker_.reset(new FrameLifetimeConsistencyChecker(contents()));
   }
 
   virtual void TearDown() OVERRIDE {
+    lifetime_checker_.reset();
     RenderViewHostImplTestHarness::TearDown();
     WebUIControllerFactory::UnregisterFactoryForTesting(&factory_);
   }
@@ -310,6 +365,7 @@ class RenderFrameHostManagerTest
 
  private:
   RenderFrameHostManagerTestWebUIControllerFactory factory_;
+  scoped_ptr<FrameLifetimeConsistencyChecker> lifetime_checker_;
 };
 
 // Tests that when you navigate from a chrome:// url to another page, and