Restore SnapshotTabHelper temporarily

chrome/common/render_messages.h

Index: chrome/common/render_messages.h
diff --git a/chrome/common/render_messages.h b/chrome/common/render_messages.h
index 57e54f76cbf7ffd9be37eb17df9ee46026c95b58..39e107757fdee61d160111114eda01aaf8282ff1 100644
--- a/chrome/common/render_messages.h
+++ b/chrome/common/render_messages.h
@@ -263,6 +263,10 @@ IPC_MESSAGE_ROUTED4(ChromeViewMsg_WebUIJavaScript,
                     int,  /* ID */
                     bool  /* If true, result is sent back. */)
 
+// Tells the render view to capture a thumbnail image of the page. The
+// render view responds with a ChromeViewHostMsg_Snapshot.
+IPC_MESSAGE_ROUTED0(ChromeViewMsg_CaptureSnapshot)
+
 // Set the content setting rules stored by the renderer.
 IPC_MESSAGE_CONTROL1(ChromeViewMsg_SetContentSettingRules,
                      RendererContentSettingRules /* rules */)
@@ -551,6 +555,10 @@ IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_CouldNotLoadPlugin,
 IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_NPAPINotSupported,
                     std::string /* identifer */)
 
+// Send a snapshot of the tab contents to the render host.
+IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_Snapshot,
+                    SkBitmap /* bitmap */)
+
 // A message for an external host.
 IPC_MESSAGE_ROUTED3(ChromeViewHostMsg_ForwardMessageToExternalHost,
                     std::string  /* message */,