<webview>: Allocate the view instance ID from the WebView shim

content/renderer/browser_plugin/mock_browser_plugin_manager.cc

Index: content/renderer/browser_plugin/mock_browser_plugin_manager.cc
diff --git a/content/renderer/browser_plugin/mock_browser_plugin_manager.cc b/content/renderer/browser_plugin/mock_browser_plugin_manager.cc
index 04dc9b6dc5d60a65e152b06d89775d04ca185818..c3b8fd8e72a22f698e99fb5a5cd6bba03533513b 100644
--- a/content/renderer/browser_plugin/mock_browser_plugin_manager.cc
+++ b/content/renderer/browser_plugin/mock_browser_plugin_manager.cc
@@ -14,7 +14,6 @@ namespace content {
 MockBrowserPluginManager::MockBrowserPluginManager(
     RenderViewImpl* render_view)
     : BrowserPluginManager(render_view),
-      browser_plugin_instance_id_counter_(0),
       guest_instance_id_counter_(0) {
 }
 
@@ -25,8 +24,7 @@ BrowserPlugin* MockBrowserPluginManager::CreateBrowserPlugin(
     RenderViewImpl* render_view,
     WebKit::WebFrame* frame,
     const WebKit::WebPluginParams& params) {
-  int instance_id = ++browser_plugin_instance_id_counter_;
-  return new MockBrowserPlugin(render_view, frame, params, instance_id);
+  return new MockBrowserPlugin(render_view, frame, params);
 }
 
 void MockBrowserPluginManager::AllocateInstanceID(