Per-host V8 histograms.

content/renderer/render_thread_impl.h

Index: content/renderer/render_thread_impl.h
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index 5ffdda184c02ec26dee41f10d9817c7e46796466..08b9293d14918ac202af4c854872348a567feb77 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -227,6 +227,15 @@ class CONTENT_EXPORT RenderThreadImpl : public content::RenderThread,
   // first call.
   content::AudioRendererMixerManager* GetAudioRendererMixerManager();
 
+  // Returns the current common host for RenderViewImpl's in this process, or an
+  // empty string, if there is no common host.

[Charlie Reis, 2012/08/21 22:46:49]

I think we need to say more about this in the comments and possibly improve the
names, since it's not clear that this isn't intended for general use.  (It has a
very specific meaning, which includes hard-coded sites and V8 histograms.)

Mainly, I wouldn't want other developers to think there's a supported concept of
a render process's common host and try to use it for other purposes.

[marja, 2012/08/22 14:59:31]

Removed this function; added ConvertToCustomHistogramName now that the needed
information is all inside RenderThreadImpl.

+  static std::string CommonHost();

[Charlie Reis, 2012/08/21 22:46:49]

This isn't virtual or complex, so it can probably be defined hacker_style() and
defined inline.

[marja, 2012/08/22 14:59:31]

This no longer exists either.

+
+  // Used for updating the information on which is the common host which all
+  // RenderView's share (if any). If there is no common host, this function is
+  // called with an empty string.
+  static void SetCommonHost(const std::string& host);
+
  private:
   virtual bool OnControlMessageReceived(const IPC::Message& msg) OVERRIDE;