Fix crash due to VisibilityTimerTabHelper not being cancelled

chrome/browser/notifications/notification_permission_context.cc

Index: chrome/browser/notifications/notification_permission_context.cc
diff --git a/chrome/browser/notifications/notification_permission_context.cc b/chrome/browser/notifications/notification_permission_context.cc
index 9e21d0c1e5e93554238051619c2236ea97f63358..73cc1a28d09cff9a1055df01e44a6d30ed376806 100644
--- a/chrome/browser/notifications/notification_permission_context.cc
+++ b/chrome/browser/notifications/notification_permission_context.cc
@@ -4,7 +4,8 @@
 
 #include "chrome/browser/notifications/notification_permission_context.h"
 
-#include <queue>
+#include <algorithm>
+#include <deque>
 
 #include "base/callback.h"
 #include "base/location.h"
@@ -38,7 +39,10 @@ class VisibilityTimerTabHelper
   // duration of at least |visible_delay|.
   void PostTaskAfterVisibleDelay(const tracked_objects::Location& from_here,
                                  const base::Closure& task,
-                                 base::TimeDelta visible_delay);
+                                 base::TimeDelta visible_delay,
+                                 const PermissionRequestID& id);
+
+  void CancelTask(const PermissionRequestID& id);

[Peter Beverloo, 2016/02/16 15:28:28]

+docs

[johnme, 2016/02/16 18:14:34]

Done.

 
   // WebContentsObserver:
   void WasShown() override;
@@ -52,7 +56,9 @@ class VisibilityTimerTabHelper
   void RunTask(const base::Closure& task);
 
   bool is_visible_;
-  std::queue<scoped_ptr<base::Timer>> task_queue_;
+
+  typedef std::pair<PermissionRequestID, scoped_ptr<base::Timer>> TaskEntry;

[Peter Beverloo, 2016/02/16 15:28:28]

Could you define a small structure instead? |task_queue_| is used a fair bit,
and the usage of {first, second} doesn't help readability.

[johnme, 2016/02/16 18:14:34]

Done.

+  std::deque<TaskEntry> task_queue_;
 
   DISALLOW_COPY_AND_ASSIGN(VisibilityTimerTabHelper);
 };
@@ -78,27 +84,46 @@ VisibilityTimerTabHelper::VisibilityTimerTabHelper(
 void VisibilityTimerTabHelper::PostTaskAfterVisibleDelay(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
-    base::TimeDelta visible_delay) {
+    base::TimeDelta visible_delay,
+    const PermissionRequestID& id) {
   // Safe to use Unretained, as destroying this will destroy task_queue_, hence
   // cancelling all timers.
-  task_queue_.push(make_scoped_ptr(new base::Timer(
-      from_here, visible_delay, base::Bind(&VisibilityTimerTabHelper::RunTask,
-                                           base::Unretained(this), task),
-      false /* is_repeating */)));
-  DCHECK(!task_queue_.back()->IsRunning());
+  task_queue_.push_back(
+      std::make_pair(id, make_scoped_ptr(new base::Timer(
+                             from_here, visible_delay,
+                             base::Bind(&VisibilityTimerTabHelper::RunTask,
+                                        base::Unretained(this), task),
+                             false /* is_repeating */))));

[Peter Beverloo, 2016/02/16 15:28:28]

nit: readability

=====
  scoped_ptr<base::Timer> timer(new base::Timer(
      from_here, visible_delay,
      base::Bind(&VisibilityTimerTabHelper::RunTask,
                 base::Unretained(this), task),
      false /* is_repeating */));

  task_queue_.push_back(std::make_pair(id, std::move(timer)));
=====

[johnme, 2016/02/16 18:14:34]

Done.

+  DCHECK(!task_queue_.back().second->IsRunning());
   if (is_visible_ && task_queue_.size() == 1)
-    task_queue_.front()->Reset();
+    task_queue_.front().second->Reset();
+}
+
+void VisibilityTimerTabHelper::CancelTask(const PermissionRequestID& id) {
+  bool deleting_front = task_queue_.front().first == id;
+  task_queue_.erase(std::remove_if(task_queue_.begin(), task_queue_.end(),
+                                   [id](const TaskEntry& entry) {
+                                     return entry.first == id;
+                                   }),
+                    task_queue_.end());
+  if (!task_queue_.empty()) {
+    if (is_visible_ && deleting_front)
+      task_queue_.front().second->Reset();
+    return;
+  }
+  web_contents()->RemoveUserData(UserDataKey());

[Peter Beverloo, 2016/02/16 15:28:28]

What is the significance of eagerly deleting |this| here? Is this just an
optimization?

[johnme, 2016/02/16 18:14:34]

It seemed neater at the time, but it adds a bunch of complexity, so I've removed
the RemoveUserData calls now, and instead I just call task_queue_.clear() in
WebContentsDestroyed.

+  // |this| has been deleted now.
 }
 
 void VisibilityTimerTabHelper::WasShown() {
   if (!is_visible_ && !task_queue_.empty())
-    task_queue_.front()->Reset();
+    task_queue_.front().second->Reset();
   is_visible_ = true;
 }
 
 void VisibilityTimerTabHelper::WasHidden() {
   if (is_visible_ && !task_queue_.empty())
-    task_queue_.front()->Stop();
+    task_queue_.front().second->Stop();
   is_visible_ = false;
 }
 
@@ -111,9 +136,9 @@ void VisibilityTimerTabHelper::WebContentsDestroyed() {
 void VisibilityTimerTabHelper::RunTask(const base::Closure& task) {
   DCHECK(is_visible_);
   task.Run();
-  task_queue_.pop();
+  task_queue_.pop_front();
   if (!task_queue_.empty()) {
-    task_queue_.front()->Reset();
+    task_queue_.front().second->Reset();
     return;
   }
   web_contents()->RemoveUserData(UserDataKey());
@@ -139,6 +164,16 @@ void NotificationPermissionContext::ResetPermission(
       profile(), ContentSettingsPattern::FromURLNoWildcard(requesting_origin));
 }
 
+void NotificationPermissionContext::CancelPermissionRequest(
+    content::WebContents* web_contents,
+    const PermissionRequestID& id) {
+  if (profile()->IsOffTheRecord()) {
+    VisibilityTimerTabHelper::FromWebContents(web_contents)->CancelTask(id);
+  } else {
+    PermissionContextBase::CancelPermissionRequest(web_contents, id);
+  }
+}
+
 void NotificationPermissionContext::DecidePermission(
     content::WebContents* web_contents,
     const PermissionRequestID& id,
@@ -166,7 +201,7 @@ void NotificationPermissionContext::DecidePermission(
                        weak_factory_ui_thread_.GetWeakPtr(), id,
                        requesting_origin, embedding_origin, callback,
                        true /* persist */, CONTENT_SETTING_BLOCK),
-            base::TimeDelta::FromSecondsD(delay_seconds));
+            base::TimeDelta::FromSecondsD(delay_seconds), id);
     return;
   }