Forcibly clear worker ref counts on shutdown.

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 47a31a45b0ed358642ef2b3eab079db44ef228ea..ec092bb46c858f512f96c897d9df8ff9325319e4 100644
--- a/content/public/browser/render_process_host.h
+++ b/content/public/browser/render_process_host.h
@@ -308,6 +308,16 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
   virtual void IncrementSharedWorkerRefCount() = 0;
   virtual void DecrementSharedWorkerRefCount() = 0;
 
+  // Sets worker ref counts to zero. Called when the browser context will be
+  // destroyed so this RenderProcessHost can immediately die.
+  //
+  // After this is called, the Increment/DecrementWorkerRefCount functions must
+  // not be called.
+  virtual void ForceReleaseWorkerRefCounts() = 0;

[jam, 2016/09/14 17:10:49]

can you put these two methods on just RenderProcessHostImpl instead of the
public interface, if they're only called from content?

[falken, 2016/09/21 08:59:43]

I can't because the AllHostsIterator can include MockRenderProcessHosts, so they
can't be casted to RenderProcessHostImpl. Is there a way to tell the difference?

[jam, 2016/09/23 19:14:28]

Is that code run during unittests though? i.e. we cast from RPH to RPHImpl for
code that we know it's run in unit tests.

+
+  // Returns true if ForceReleaseWorkerRefCounts was called.
+  virtual bool IsWorkerRefCountDisabled() = 0;
+
   // Purges and suspends the renderer process.
   virtual void PurgeAndSuspend() = 0;