Handle interface to prerenders.

chrome/browser/prerender/prerender_handle.h

Index: chrome/browser/prerender/prerender_handle.h
diff --git a/chrome/browser/prerender/prerender_handle.h b/chrome/browser/prerender/prerender_handle.h
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index 0000000000000000000000000000000000000000..8434c4e6748846325cca65a43cea11604e3d94e6
--- /dev/null
+++ b/chrome/browser/prerender/prerender_handle.h
@@ -0,0 +1,79 @@
+// 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.
+
+#ifndef CHROME_BROWSER_PRERENDER_PRERENDER_HANDLE_H_
+#define CHROME_BROWSER_PRERENDER_PRERENDER_HANDLE_H_
+
+#include <list>

[mmenke, 2012/07/09 18:06:57]

Not needed.

[gavinp, 2012/07/11 17:04:00]

Done.

+
+#include "base/memory/weak_ptr.h"
+#include "base/threading/non_thread_safe.h"

[mmenke, 2012/07/09 18:06:57]

base/basictypes.h should be here instead of in the cc files, since it's where
DISALLOW_COPY_AND_ASSIGN is defined.

[gavinp, 2012/07/11 17:04:00]

Done.

+
+class GURL;
+
+namespace content {
+class SessionStorageNamespace;
+}
+
+namespace prerender {
+
+class PrerenderContents;
+class PrerenderManager;
+
+class PrerenderHandle : public base::NonThreadSafe {
+ public:
+  ~PrerenderHandle();

[mmenke, 2012/07/09 18:06:57]

Suggest a comment that this calls OnCancel automatically.

[gavinp, 2012/07/11 17:04:00]

Done.

+
+  // The launcher is navigating away from the context that launched this
+  // prerender. The prerender will likely stay alive briefly though, in case we
+  // are going through a redirect chain that will target it. This call
+  // invalidates the handle.
+  void OnNavigateAway();
+
+  // The launcher has taken explicit action to remove this prerender (for
+  // instance, removing a link element from a document). This call invalidates
+  // the handle.

[mmenke, 2012/07/09 18:06:57]

Suggest a comment that it does nothing if abandoned.

[gavinp, 2012/07/11 17:04:00]

I've tried hard to get rid of a lot of the abandoned terminology, it was
confusing. I'm not sure what you're asking for. Can you expand on your request
for me?

[mmenke, 2012/07/11 18:40:05]

Sure.  I just want it clear that "OnNavigateAway(); OnCancel();" does not, in
fact, cancel.  Could either say that explicity, or say it does nothing when the
handle isn't valid.

[gavinp, 2012/07/11 21:19:30]

Done.

+  void OnCancel();
+
+  // True if the prerender (pending or running) has not been deleted out from
+  // under this handle.
+  bool IsValid() const { return prerender_data_ != NULL; }

[mmenke, 2012/07/09 18:06:57]

Don't inline this - style guide strongly discourages inlining anything other
than simple getters/setters, and skimming over over files, tiny IsValid and
is_valid functions (Both of which are about equally as common) look to be
generally not inlined, despite being somewhat simple getter-ish.

[gavinp, 2012/07/11 17:04:00]

Done.

+
+  // True if this prerender was launched by a page that was itself being
+  // prerendered, and so has not yet been started.
+  bool IsPending() const;
+
+  // True if this prerender is currently running.

[mmenke, 2012/07/09 18:06:57]

nit:  "running" is ambiguous (Is an idle, loaded webpage "running", or what
about an idle prerender that's waiting for other prerenders to go aware before
starting (Not a current state, but could theoretically want it in the future)). 
Suggest "is currently active" or even "has an active PrerenderContents", though
that might be exposing more details than we want to consumers.

[gavinp, 2012/07/11 17:04:00]

Done.

+  bool IsPrerendering() const;
+
+  bool DidFinishLoading() const;

[mmenke, 2012/07/09 18:06:57]

Suggest IsFinishedLoading().  If a prerender finishes loading, but then is
cancelled, it did finish loading, but DidFinishLoading returns false.

[gavinp, 2012/07/11 17:04:00]

Done.

+
+ private:
+  friend class PrerenderBrowserTest;
+  friend class PrerenderManager;
+
+  struct PrerenderData {
+    explicit PrerenderData(PrerenderManager* manager);
+    PrerenderData(PrerenderManager* manager,
+                  PrerenderContents* contents);
+
+    PrerenderManager* manager;
+    PrerenderContents* contents;
+    int instance_count;
+  };
+
+  PrerenderHandle();
+  explicit PrerenderHandle(base::WeakPtr<PrerenderData> prerender_data);
+
+  void SwapPrerenderDataWith(PrerenderHandle* other_prerender_handle);
+
+  base::WeakPtr<PrerenderData> prerender_data_;
+  base::WeakPtrFactory<PrerenderHandle> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrerenderHandle);
+};
+
+}  // namespace prerender
+
+#endif  // CHROME_BROWSER_PRERENDER_PRERENDER_HANDLE_H_