Make PrerenderHandle an observer of PrerenderContents.

chrome/browser/prerender/prerender_link_manager.cc

Index: chrome/browser/prerender/prerender_link_manager.cc
diff --git a/chrome/browser/prerender/prerender_link_manager.cc b/chrome/browser/prerender/prerender_link_manager.cc
index ea559977e272d5c0eeace49991130a88ad22457d..f7dd37ef10fae4fe324270f5fdf9dcc89e280d1d 100644
--- a/chrome/browser/prerender/prerender_link_manager.cc
+++ b/chrome/browser/prerender/prerender_link_manager.cc
@@ -8,11 +8,14 @@
 #include <queue>
 #include <utility>
 
+#include "base/memory/scoped_ptr.h"
 #include "chrome/browser/prerender/prerender_contents.h"
 #include "chrome/browser/prerender/prerender_handle.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/common/prerender_messages.h"
+#include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/session_storage_namespace.h"
 #include "content/public/common/referrer.h"
@@ -22,6 +25,20 @@
 using content::RenderViewHost;
 using content::SessionStorageNamespace;
 
+namespace {
+
+void Send(int child_id, IPC::Message* raw_message) {
+  scoped_ptr<IPC::Message> own_message(raw_message);
+  using content::RenderProcessHost;
+
+  RenderProcessHost* render_process_host = RenderProcessHost::FromID(child_id);
+  if (!render_process_host)
+    return;
+  render_process_host->Send(own_message.release());
+}
+
+}  // namespace
+
 namespace prerender {
 
 PrerenderLinkManager::PrerenderLinkManager(PrerenderManager* manager)
@@ -33,7 +50,9 @@ PrerenderLinkManager::~PrerenderLinkManager() {
        it != ids_to_handle_map_.end();
        ++it) {
     PrerenderHandle* prerender_handle = it->second;
-    prerender_handle->OnCancel();
+    DCHECK(!prerender_handle->IsPrerendering())
+        << "All running prerenders should stop at the same time as the "
+        << "PrerenderManager.";
     delete prerender_handle;
   }
 }
@@ -51,29 +70,25 @@ bool PrerenderLinkManager::OnAddPrerender(int child_id,
            << ", size = (" << size.width() << ", " << size.height() << ")"
            << ", render_view_route_id = " << render_view_route_id;
 
+
+  PrerenderHandle* prerender_handle =
+      manager_-> AddPrerenderFromLinkRelPrerender(

[mmenke, 2012/12/12 16:54:12]

nit:  Remove space

[gavinp, 2012/12/13 13:38:03]

Done.

+          child_id, render_view_route_id, url, referrer, size);
+  if (!prerender_handle)
+    return false;
+
   const ChildAndPrerenderIdPair child_and_prerender_id(child_id, prerender_id);
-  DCHECK_EQ(0U, ids_to_handle_map_.count(child_and_prerender_id));
-
-  scoped_ptr<PrerenderHandle> prerender_handle(
-      manager_->AddPrerenderFromLinkRelPrerender(
-          child_id, render_view_route_id, url, referrer, size));
-  if (prerender_handle.get()) {
-    std::pair<IdPairToPrerenderHandleMap::iterator, bool> insert_result =
-        ids_to_handle_map_.insert(std::make_pair(
-            child_and_prerender_id, static_cast<PrerenderHandle*>(NULL)));
-    DCHECK(insert_result.second);
-    delete insert_result.first->second;
-    insert_result.first->second = prerender_handle.release();
-    return true;
-  }
-  return false;
+  DCHECK_EQ(0u, ids_to_handle_map_.count(child_and_prerender_id));
+  ids_to_handle_map_[child_and_prerender_id] = prerender_handle;
+
+  // If we are given a prerender that is already prerendering, we have missed
+  // the start event.
+  if (prerender_handle->IsPrerendering())
+    OnPrerenderStart(prerender_handle);
+  prerender_handle->AddObserver(this);
+  return true;
 }
 
-// TODO(gavinp): Once an observer interface is provided down to the WebKit
-// layer, we should add DCHECK_NE(0L, ids_to_url_map_.count(...)) to both
-// OnCancelPrerender and OnAbandonPrerender. We can't do this now, since
-// the WebKit layer isn't even aware if we didn't add the prerender to the map
-// in OnAddPrerender above.
 void PrerenderLinkManager::OnCancelPrerender(int child_id, int prerender_id) {
   DVLOG(2) << "OnCancelPrerender, child_id = " << child_id
            << ", prerender_id = " << prerender_id;
@@ -86,7 +101,12 @@ void PrerenderLinkManager::OnCancelPrerender(int child_id, int prerender_id) {
   }
   PrerenderHandle* prerender_handle = id_to_handle_iter->second;
   prerender_handle->OnCancel();
-  RemovePrerender(id_to_handle_iter);
+
+  // OnCancel may end up calling back into OnPrerenderStop, and so
+  // |id_to_handle_iter| must be treated as invalidated.
+  id_to_handle_iter = ids_to_handle_map_.find(child_and_prerender_id);
+  if (id_to_handle_iter != ids_to_handle_map_.end())
+    RemovePrerender(id_to_handle_iter);
 }
 
 void PrerenderLinkManager::OnAbandonPrerender(int child_id, int prerender_id) {
@@ -99,7 +119,12 @@ void PrerenderLinkManager::OnAbandonPrerender(int child_id, int prerender_id) {
     return;
   PrerenderHandle* prerender_handle = id_to_handle_iter->second;
   prerender_handle->OnNavigateAway();
-  RemovePrerender(id_to_handle_iter);
+
+  // OnCancel may end up calling back into OnPrerenderStop, and so

[mmenke, 2012/12/11 19:53:45]

nit:  OnNavigateAway.

[mmenke, 2012/12/11 19:53:45]

Actually...Is there any way that OnNavigateAway would end up calling into
OnPrerenderStop?

[gavinp, 2012/12/13 13:38:03]

No. But we also need to leave the prerender in the map, since if the prerender
continues discovering new aliases, we want those to make it down to the
prerender dispatcher. So I've just tossed this whole code block out.

+  // |id_to_handle_iter| must be treated as invalidated.
+  id_to_handle_iter = ids_to_handle_map_.find(child_and_prerender_id);
+  if (id_to_handle_iter != ids_to_handle_map_.end())
+    RemovePrerender(id_to_handle_iter);
 }
 
 void PrerenderLinkManager::OnChannelClosing(int child_id) {
@@ -134,4 +159,56 @@ void PrerenderLinkManager::RemovePrerender(
   ids_to_handle_map_.erase(id_to_handle_iter);
 }
 
+PrerenderLinkManager::IdPairToPrerenderHandleMap::iterator
+PrerenderLinkManager::FindPrerenderHandle(
+    PrerenderHandle* prerender_handle) {
+  for (IdPairToPrerenderHandleMap::iterator it = ids_to_handle_map_.begin();
+       it != ids_to_handle_map_.end(); ++it) {
+    if (it->second == prerender_handle)
+      return it;
+  }
+  return ids_to_handle_map_.end();
+}
+
+// In practice, this is always called from either
+// PrerenderLinkManager::OnAddPrerender in the regular case, or in the pending
+// prerender case, from PrerenderHandle::AdoptPrerenderDataFrom.
+void PrerenderLinkManager::OnPrerenderStart(
+    PrerenderHandle* prerender_handle) {
+  IdPairToPrerenderHandleMap::iterator it =
+      FindPrerenderHandle(prerender_handle);
+  if (it == ids_to_handle_map_.end())

[mmenke, 2012/12/11 19:53:45]

Does this ever happen?  Same goes for the next two functions.

We add a handle to the map at the same point we start listening to it.

RemovePrerender both removes the handle from the map and deletes it.

[gavinp, 2012/12/13 13:38:03]

Good point. Now a DCHECK.

+    return;
+  const int child_id = it->first.first;
+  const int prerender_id = it->first.second;
+
+  Send(child_id, new PrerenderMsg_OnPrerenderStart(prerender_id));
+}
+
+void PrerenderLinkManager::OnPrerenderAddAlias(
+    PrerenderHandle* prerender_handle,
+    const GURL& alias_url) {
+  IdPairToPrerenderHandleMap::iterator it =
+      FindPrerenderHandle(prerender_handle);
+  if (it == ids_to_handle_map_.end())
+    return;
+  const int child_id = it->first.first;
+  const int prerender_id = it->first.second;
+
+  Send(child_id, new PrerenderMsg_OnPrerenderAddAlias(prerender_id, alias_url));
+}
+
+void PrerenderLinkManager::OnPrerenderStop(
+    PrerenderHandle* prerender_handle) {
+  IdPairToPrerenderHandleMap::iterator it =
+      FindPrerenderHandle(prerender_handle);
+  if (it == ids_to_handle_map_.end())
+    return;
+  const int child_id = it->first.first;
+  const int prerender_id = it->first.second;
+
+  Send(child_id, new PrerenderMsg_OnPrerenderStop(prerender_id));
+  RemovePrerender(it);
+}
+
 }  // namespace prerender