Implemented GetWindowSnapshot on RenderViewImpl

content/common/view_messages.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.
 
 // IPC messages for page rendering.
 // Multiply-included message file, hence no include guard.
 
 #include "base/process.h"
 #include "base/shared_memory.h"
 #include "base/string16.h"
@@ skipping 1427 matching lines @@
 // External popup menus.
 IPC_MESSAGE_ROUTED1(ViewMsg_SelectPopupMenuItem,
                     int /* selected index, -1 means no selection */)
 #endif
 
 // An acknowledge to ViewHostMsg_MultipleTargetsTouched to notify the renderer
 // process to release the magnified image.
 IPC_MESSAGE_ROUTED1(ViewMsg_ReleaseDisambiguationPopupDIB,
                     TransportDIB::Handle /* DIB handle */)
 
+// Notifies the renderer that a snapshot has been retrieved.
+IPC_MESSAGE_ROUTED3(ViewMsg_WindowSnapshotCompleted,
+                    int /* snapshot_id */,
+                    gfx::Size /* size */,
+                    std::vector<unsigned char> /* png */)
+
 // -----------------------------------------------------------------------------
 // Messages sent from the renderer to the browser.
 
 // Sent by the renderer when it is creating a new window.  The browser creates
 // a tab for it and responds with a ViewMsg_CreatingNew_ACK.  If route_id is
 // MSG_ROUTING_NONE, the view couldn't be created.
 IPC_SYNC_MESSAGE_CONTROL1_3(ViewHostMsg_CreateWindow,
                             ViewHostMsg_CreateWindow_Params,
                             int /* route_id */,
                             int32 /* surface_id */,
@@ skipping 475 matching lines @@
 IPC_MESSAGE_ROUTED1(ViewHostMsg_HasTouchEventHandlers,
                     bool /* has_handlers */)
 
 // A message from HTML-based UI.  When (trusted) Javascript calls
 // send(message, args), this message is sent to the browser.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_WebUISend,
                     GURL /* source_url */,
                     std::string  /* message */,
                     base::ListValue /* args */)
 
+// Requests a snapshot of the given window.
+IPC_MESSAGE_ROUTED1(ViewHostMsg_GetWindowSnapshot,
+                    int /* message id */)

[Ken Russell (switch to Gerrit), 2012/11/30 22:32:54]

For clarity, change "message id" to "snapshot_id". Also, @jam's indicated to me
that the arguments of the message handler should match the names in these
comments.

+
 // A renderer sends this to the browser process when it wants to create a ppapi
 // plugin.  The browser will create the plugin process if necessary, and will
 // return a handle to the channel on success.
 //
 // The plugin_child_id is the ChildProcessHost ID assigned in the browser
 // process. This ID is valid only in the context of the browser process and is
 // used to identify the proper process when the renderer notifies it that the
 // plugin is hung.
 //
 // On error an empty string and null handles are returned.
@@ skipping 479 matching lines @@
                      int /* arb_robustness_status_code */)
 
 #if defined(OS_WIN)
 // Request that the given font characters be loaded by the browser so it's
 // cached by the OS. Please see RenderMessageFilter::OnPreCacheFontCharacters
 // for details.
 IPC_SYNC_MESSAGE_CONTROL2_0(ViewHostMsg_PreCacheFontCharacters,
                             LOGFONT /* font_data */,
                             string16 /* characters */)
 #endif