Determine the element location and click synchronously on the renderer.

chrome/common/automation_messages_internal.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Defines the IPC messages used by the automation interface.
 
 // NOTE: All IPC messages have either a routing_id of 0 (for asynchronous
 //       messages), or one that's been assigned by the proxy (for calls
 //       which expect a response).  The routing_id shouldn't be used for
 //       any other purpose in these message types.
@@ skipping 1504 matching lines @@
 
 // Requests a snapshot.
 IPC_MESSAGE_ROUTED0(AutomationMsg_SnapshotEntirePage)
 
 #if !defined(NO_TCMALLOC) && (defined(OS_LINUX) || defined(OS_CHROMEOS))
 // Requests to dump a heap profile.
 IPC_MESSAGE_ROUTED1(AutomationMsg_HeapProfilerDump,
                     std::string /* reason */)
 #endif  // !defined(NO_TCMALLOC) && (defined(OS_LINUX) || defined(OS_CHROMEOS))
 
+// Requests processing of the given mouse event.
+IPC_MESSAGE_ROUTED1(AutomationMsg_ProcessMouseEvent,
+                    AutomationMouseEvent)

[dennis_jeffrey, 2012/05/08 19:18:49]

This will change the line numbers of the entries below.  I was concerned about
the message at lines 12-18 above, but I think it's ok here, since this is a
browser <--> renderer message.  However, just want to bring this to your
attention to double-check, since I'm not sure about this. 

[kkania, 2012/05/09 18:19:59]

Yes, this is ok.

+
 // Renderer -> browser messages.
 
 // Sent as a response to |AutomationMsg_Snapshot|.
 IPC_MESSAGE_ROUTED3(AutomationMsg_SnapshotEntirePageACK,
                     bool /* success */,
                     std::vector<unsigned char> /* png bytes */,
                     std::string /* error message */)
 
 // Sent when the renderer has scheduled a client redirect to occur.
 IPC_MESSAGE_ROUTED2(AutomationMsg_WillPerformClientRedirect,
                     int64 /* frame_id */,
                     double /* # of seconds till redirect will be performed */)
 
 // Sent when the renderer has completed or canceled a client redirect for a
 // particular frame. This message may be sent multiple times for the same
 // redirect.
 IPC_MESSAGE_ROUTED1(AutomationMsg_DidCompleteOrCancelClientRedirect,
                     int64 /* frame_id */)
 
+// Sent right before processing a mouse event at the given point.
+// This is needed in addition to AutomationMsg_ProcessMouseEventACK so that
+// the client knows where the event occurred even if the event causes a modal
+// dialog to appear which blocks further messages.
+IPC_MESSAGE_ROUTED1(AutomationMsg_WillProcessMouseEventAt,
+                    gfx::Point)
+
+// Sent when the automation mouse event has been processed.
+IPC_MESSAGE_ROUTED2(AutomationMsg_ProcessMouseEventACK,
+                    bool /* success */,
+                    std::string /* error message */)
+

[dennis_jeffrey, 2012/05/08 19:18:49]

nit: remove this blank line

[kkania, 2012/05/09 18:19:59]

Done.

+
 // YOUR NEW MESSAGE MIGHT NOT BELONG HERE.
 // This is the section for renderer -> browser automation messages. If it is
 // an automation <-> browser message, put it above this section. The "no line
 // number change" applies only to the automation <-> browser messages.