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

content/common/page_messages.h

Index: content/common/page_messages.h
diff --git a/content/common/page_messages.h b/content/common/page_messages.h
index 284c134508b5d9227303ec5f96ec52235e628176..a7f56bb85164905f5b3d4b9d23c2bfe69975e327 100644
--- a/content/common/page_messages.h
+++ b/content/common/page_messages.h
@@ -2,7 +2,9 @@
 // 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.
@@ -12,11 +14,19 @@
 
 #define IPC_MESSAGE_START PageMsgStart
 
+IPC_ENUM_TRAITS_MAX_VALUE(
+    PageMsg_SetZoomLevel_Command,
+    PageMsg_SetZoomLevel_Command::LAST);
+
 // 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.