Modify ProfileDestroyer to prevent leaks.

chrome/browser/profiles/profile_destroyer.cc

 // 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 "chrome/browser/profiles/profile_destroyer.h"
 
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_process_host.h"
 
+
+namespace {
+
+const int64 kTimerDelaySeconds = 1;
+
+}  // namespace
+
+std::vector<ProfileDestroyer*>* ProfileDestroyer::pending_destroyers_ = NULL;
+
 // static
 void ProfileDestroyer::DestroyProfileWhenAppropriate(Profile* const profile) {
+  DCHECK(profile);
   std::vector<content::RenderProcessHost*> hosts;
   // Testing profiles can simply be deleted directly. Some tests don't setup
   // RenderProcessHost correctly and don't necessary run on the UI thread
   // anyway, so we can't use the AllHostIterator.
   if (profile->AsTestingProfile() == NULL) {
     GetHostsForProfile(profile, &hosts);
     if (!profile->IsOffTheRecord() && profile->HasOffTheRecordProfile())
       GetHostsForProfile(profile->GetOffTheRecordProfile(), &hosts);
   }
-  if (hosts.empty()) {
+  // This should never happen for non Off the record profile, this means that
+  // there is a leak in a render process host that MUST BE FIXED!!!
+  DCHECK(hosts.empty() || profile->IsOffTheRecord());
+  // Note that we still test for !profile->IsOffTheRecord here even though we
+  // DCHECK'd above because we want to protect Release builds against this even
+  // we need to identify if there are leaks when we run Debug builds.
+  if (hosts.empty() || !profile->IsOffTheRecord()) {
     if (profile->IsOffTheRecord())
       profile->GetOriginalProfile()->DestroyOffTheRecordProfile();
     else
       delete profile;
   } else {
     // The instance will destroy itself once all render process hosts referring
-    // to it and/or it's off the record profile are properly terminated.
+    // to it are properly terminated.
     scoped_refptr<ProfileDestroyer> profile_destroyer(
         new ProfileDestroyer(profile, hosts));
   }
 }
 
+// This can be called to cancel any pending destruction and destroy the profile
+// now, e.g., if the parent profile is being destroyed while the incognito one
+// still pending...
+void ProfileDestroyer::DestroyOffTheRecordProfileNow(Profile* const profile) {
+  DCHECK(profile);
+  DCHECK(profile->IsOffTheRecord());
+  if (pending_destroyers_) {
+    for (size_t i = 0; i < pending_destroyers_->size(); ++i) {
+      if ((*pending_destroyers_)[i]->profile_ == profile) {
+        // We want to signal this in debug builds so that we don't lose sight of
+        // these potential leaks, but we handle it in release so that we don't
+        // crash or corrupt profile data on disk.
+        NOTREACHED() << "A render process host wasn't destroyed early enough.";
+        (*pending_destroyers_)[i]->profile_ = NULL;
+        break;
+      }
+    }
+  }
+  DCHECK(profile->GetOriginalProfile());
+  profile->GetOriginalProfile()->DestroyOffTheRecordProfile();
+}
+
 ProfileDestroyer::ProfileDestroyer(
     Profile* const profile,
-    const std::vector<content::RenderProcessHost*>& hosts) : profile_(profile) {
+    const std::vector<content::RenderProcessHost*>& hosts)
+    : timer_(false, false),
+      num_hosts_(0),
+      profile_(profile) {
+  if (pending_destroyers_ == NULL)
+    pending_destroyers_ = new std::vector<ProfileDestroyer*>;
+  pending_destroyers_->push_back(this);
   for (size_t i = 0; i < hosts.size(); ++i) {
     registrar_.Add(this, content::NOTIFICATION_RENDERER_PROCESS_TERMINATED,
         content::Source<content::RenderProcessHost>(hosts[i]));
     // For each of the notifications, we bump up our reference count.
     // It will go back to 0 and free us when all hosts are terminated.
-    AddRef();
+    ++num_hosts_;
+  }
+  // If we are going to wait for render process hosts, we don't want to do it
+  // for longer than kTimerDelaySeconds.
+  if (num_hosts_) {
+    timer_.Start(FROM_HERE,
+                 base::TimeDelta::FromSeconds(kTimerDelaySeconds),
+                 base::Bind(&ProfileDestroyer::DestroyProfile, this));
   }
 }
 
 ProfileDestroyer::~ProfileDestroyer() {
   // Check again, in case other render hosts were added while we were
   // waiting for the previous ones to go away...
-  DestroyProfileWhenAppropriate(profile_);
+  if (profile_)
+    DestroyProfileWhenAppropriate(profile_);
+
+  // We shouldn't be deleted with pending notifications.
+  DCHECK(registrar_.IsEmpty());
+
+  DCHECK(pending_destroyers_ != NULL);
+  std::vector<ProfileDestroyer*>::iterator iter = std::find(
+      pending_destroyers_->begin(), pending_destroyers_->end(), this);
+  DCHECK(iter != pending_destroyers_->end());
+  pending_destroyers_->erase(iter);
+  DCHECK(pending_destroyers_->end() == std::find(pending_destroyers_->begin(),
+                                                 pending_destroyers_->end(),
+                                                 this));
+  if (pending_destroyers_->empty()) {
+    delete pending_destroyers_;
+    pending_destroyers_ = NULL;
+  }
 }
 
 void ProfileDestroyer::Observe(int type,
                                const content::NotificationSource& source,
                                const content::NotificationDetails& details) {
   DCHECK(type == content::NOTIFICATION_RENDERER_PROCESS_TERMINATED);
-  // Delay the destruction one step further in case other observers of this
-  // notification need to look at the profile attached to the host.
-  MessageLoop::current()->PostTask(
-      FROM_HERE, base::Bind(&ProfileDestroyer::Release, this));
+  DCHECK(num_hosts_ > 0);
+  --num_hosts_;
+  if (num_hosts_ == 0) {
+    // Delay the destruction one step further in case other observers of this
+    // notification need to look at the profile attached to the host.
+    MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(&ProfileDestroyer::DestroyProfile, this));
+  }
+}
+
+void ProfileDestroyer::DestroyProfile() {
+  // We might have been cancelled externally before the timer expired.
+  if (profile_ == NULL)
+    return;
+  DCHECK(profile_->IsOffTheRecord());
+  DCHECK(profile_->GetOriginalProfile());
+  profile_->GetOriginalProfile()->DestroyOffTheRecordProfile();
+  profile_ = NULL;
+
+  // Don't wait for pending registrations, if any, these hosts are buggy.
+  DCHECK(registrar_.IsEmpty()) << "Some render process hosts where not "
+                               << "destroyed early enough!";
+  registrar_.RemoveAll();
+
+  // And stop the timer so we can be released early too.
+  timer_.Stop();
 }
 
 // static
 bool ProfileDestroyer::GetHostsForProfile(
     Profile* const profile, std::vector<content::RenderProcessHost*>* hosts) {
   for (content::RenderProcessHost::iterator iter(
         content::RenderProcessHost::AllHostsIterator());
       !iter.IsAtEnd(); iter.Advance()) {
     content::RenderProcessHost* render_process_host = iter.GetCurrentValue();
     if (render_process_host && Profile::FromBrowserContext(
           render_process_host->GetBrowserContext()) == profile) {
       hosts->push_back(render_process_host);
     }
   }
   return !hosts->empty();
 }