MemoryCoordinator checks if ServiceWorker exists on the suspending process

content/public/browser/render_process_host.h

Index: content/public/browser/render_process_host.h
diff --git a/content/public/browser/render_process_host.h b/content/public/browser/render_process_host.h
index 8edeb8458a3428f17d5d3b0b7348886335a15989..30a96f368a57b2621e8f4bf94593651c7f756e0e 100644
--- a/content/public/browser/render_process_host.h
+++ b/content/public/browser/render_process_host.h
@@ -304,10 +304,11 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
   // Returns true if this process currently has backgrounded priority.
   virtual bool IsProcessBackgrounded() const = 0;
 
-  // Called when the existence of the other renderer process which is connected
-  // to the Worker in this renderer process has changed.
+  virtual size_t GetWorkerRefCount() const = 0;
   virtual void IncrementServiceWorkerRefCount() = 0;
   virtual void DecrementServiceWorkerRefCount() = 0;

[Avi (use Gerrit), 2016/12/14 06:41:07]

Extra blank line after these lines.

Please add a comment for what these functions do. 

[shimazu, 2016/12/14 08:01:20]

Done.

+  // Called when the existence of the other renderer process which is connected
+  // to the Worker in this renderer process has changed.

[Avi (use Gerrit), 2016/12/14 06:41:07]

This sentence is hard to follow. Can you clarify?

[falken, 2016/12/14 06:58:51]

Yea this is complex but not from this patch. I meant to fix these the last time
I understood them. The shared worker ref count in RPH is really more like a
boolean flag tracking whether any other renderer process is connected to a
shared worker in this renderer process. If there was none, and now there is at
least one, Increment is called. If there was at least one, and now there is none
Decrement is called. However Increment is *also* called when starting a new
shared worker, so the process that houses it does not die in the middle of
creation. So I suggest:

"The shared worker ref count is nonzero if any other process is connected to a
shared worker in this process, or a new shared worker is being created in this
process. IncrementSharedWorkerRefCount is called in two cases:
- there was no external renderer connected to a shared worker in this process,
and now there is at least one
- a new worker is being created in this process."
DecrementSharedWorkerRefCount is called in two cases:
- there was an external renderer connected to a shared worker in this process,
and now there is none
- a new worker finished being created in this process."

[shimazu, 2016/12/14 08:01:20]

Updated the comment, thanks!

   virtual void IncrementSharedWorkerRefCount() = 0;
   virtual void DecrementSharedWorkerRefCount() = 0;