Move RenderViewHostObserver to content/public/browser/ and put it into the content namespace.

content/public/browser/render_view_host_observer.h

Index: content/public/browser/render_view_host_observer.h
diff --git a/content/browser/renderer_host/render_view_host_observer.h b/content/public/browser/render_view_host_observer.h
similarity index 87%
rename from content/browser/renderer_host/render_view_host_observer.h
rename to content/public/browser/render_view_host_observer.h
index 3067f4318580c4310c8407085cbada54740fae12..bd68fae0dbb88f75dbed774e11fab520b8e9ff5f 100644
--- a/content/browser/renderer_host/render_view_host_observer.h
+++ b/content/public/browser/render_view_host_observer.h
@@ -2,8 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_OBSERVER_H_
-#define CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_OBSERVER_H_
+#ifndef CONTENT_PUBLIC_BROWSER_RENDER_VIEW_HOST_OBSERVER_H_
+#define CONTENT_PUBLIC_BROWSER_RENDER_VIEW_HOST_OBSERVER_H_
+#pragma once
 
 #include "ipc/ipc_channel.h"
 #include "content/common/content_export.h"
@@ -11,6 +12,8 @@
 class GURL;
 class RenderViewHost;
 
+namespace content {
+
 // An observer API implemented by classes which want to filter IPC messages from
 // RenderViewHost.
 class CONTENT_EXPORT RenderViewHostObserver : public IPC::Channel::Listener,
@@ -45,7 +48,7 @@ class CONTENT_EXPORT RenderViewHostObserver : public IPC::Channel::Listener,
   int routing_id() { return routing_id_; }
 
  private:
-  friend class RenderViewHost;
+  friend class ::RenderViewHost;
 
   // Invoked from RenderViewHost. Invokes RenderViewHostDestroyed and NULL out
   // |render_view_host_|.
@@ -59,4 +62,6 @@ class CONTENT_EXPORT RenderViewHostObserver : public IPC::Channel::Listener,
   DISALLOW_COPY_AND_ASSIGN(RenderViewHostObserver);
 };
 
-#endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_OBSERVER_H_
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_RENDER_VIEW_HOST_OBSERVER_H_