Bug 797239 - Fix message loop to allow idle tasks to work in child content processes. r=cjones

ipc/chromium/src/base/message_loop.cc

@@ -90,6 +90,7 @@ MessageLoop::MessageLoop(Type type)
       nestable_tasks_allowed_(true),
       exception_restoration_(false),
       state_(NULL),
+      run_depth_base_(1),
 #ifdef OS_WIN
       os_modal_loop_(false),
 #endif  // OS_WIN
@@ -102,6 +103,12 @@ MessageLoop::MessageLoop(Type type)
   }
   if (type_ == TYPE_MOZILLA_CHILD) {
     pump_ = new mozilla::ipc::MessagePumpForChildProcess();
+    // There is a MessageLoop Run call from XRE_InitChildProcess
+    // and another one from MessagePumpForChildProcess. The one
+    // from MessagePumpForChildProcess becomes the base, so we need
+    // to set run_depth_base_ to 2 or we'll never be able to process
+    // Idle tasks.
+    run_depth_base_ = 2;
     return;
   }
 
@@ -212,7 +219,7 @@ void MessageLoop::RunInternal() {
 // Wrapper functions for use in above message loop framework.
 
 bool MessageLoop::ProcessNextDelayedNonNestableTask() {
-  if (state_->run_depth != 1)
+  if (state_->run_depth > run_depth_base_)
     return false;
 
   if (deferred_non_nestable_work_queue_.empty())
@@ -330,7 +337,7 @@ void MessageLoop::RunTask(Task* task) {
 }
 
 bool MessageLoop::DeferOrRunPendingTask(const PendingTask& pending_task) {
-  if (pending_task.nestable || state_->run_depth == 1) {
+  if (pending_task.nestable || state_->run_depth >= run_depth_base_) {
     RunTask(pending_task.task);
     // Show that we ran a task (Note: a new one might arrive as a
     // consequence!).

ipc/chromium/src/base/message_loop.h

@@ -408,6 +408,7 @@ public:
   Lock incoming_queue_lock_;
 
   RunState* state_;
+  int run_depth_base_;
 
 #if defined(OS_WIN)
   // Should be set to true before calling Windows APIs like TrackPopupMenu, etc