Fix page zoom to be frame-centric for out-of-process frames.

content/common/page_messages.h

 // Copyright 2016 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.
 
+#include "content/common/page_message_enums.h"
 #include "ipc/ipc_message_macros.h"
+#include "ui/gfx/geometry/rect.h"
 
 // IPC messages for page-level actions.
 // Multiply-included message file, hence no include guard.
 
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 
 #define IPC_MESSAGE_START PageMsgStart
 
+IPC_ENUM_TRAITS_MAX_VALUE(
+    PageMsg_SetZoomLevel_Command,
+    PageMsg_SetZoomLevel_Command::ZOOM_USE_CURRENT_TEMPORARY_MODE);

[alexmos, 2016/04/11 23:19:11]

It might be a good idea to define a PageMsg_SetZoomLevel_Command::LAST (=
USE_CURRENT_TEMPORARY_MODE in enum class) and use it here.  That way this won't
get out of date if a new command is added to the enum.  Many, though not all,
frame and view messages seem to use this pattern, so I'm guessing this is not
required but nice to have.

[wjmaclean, 2016/04/13 18:47:47]

Done.

+
 // Messages sent from the browser to the renderer.
 
 IPC_MESSAGE_ROUTED1(PageMsg_UpdateWindowScreenRect,
                     gfx::Rect /* window_screen_rect */)
 
+IPC_MESSAGE_ROUTED2(PageMsg_SetZoomLevel,
+                    PageMsg_SetZoomLevel_Command /* command */,
+                    double /* zoom_level */)
+
 // -----------------------------------------------------------------------------
 // Messages sent from the renderer to the browser.
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent PageMsg, then ifdefs for platform specific PageMsg, then platform
 // independent PageHostMsg, then ifdefs for platform specific PageHostMsg.