Implementation of device metrics emulation in render view.

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/memory/shared_memory.h"
 #include "base/process/process.h"
 #include "base/strings/string16.h"
@@ skipping 868 matching lines @@
 IPC_MESSAGE_ROUTED0(ViewMsg_UpdateRect_ACK)
 
 // Tells the render view that a SwapBuffers was completed. Typically,
 // SwapBuffers requests go from renderer -> GPU process -> browser. Most
 // platforms still use the GfxCxt3D Echo for receiving the SwapBuffers Ack.
 // Using Echo routes the ack from browser -> GPU process -> renderer, while this
 // Ack goes directly from browser -> renderer. This is not used for the threaded
 // compositor path.
 IPC_MESSAGE_ROUTED0(ViewMsg_SwapBuffers_ACK)
 
+// Tells the render view that a ViewHostMsg_EmulateDevice message
+// was processed. This signals the render view that it's safe to emulate,
+// and host will accept rendered image of any size.
+IPC_MESSAGE_ROUTED1(ViewMsg_EmulateDevice_ACK,
+                    bool /* enabled */)
+
 // Tells the render widget that a smooth scroll completed.
 IPC_MESSAGE_ROUTED0(ViewMsg_SmoothScrollCompleted)
 
 // Tells the renderer to focus the first (last if reverse is true) focusable
 // node.
 IPC_MESSAGE_ROUTED1(ViewMsg_SetInitialFocus,
                     bool /* reverse */)
 
 // Executes custom context menu action that was provided from WebKit.
 IPC_MESSAGE_ROUTED2(ViewMsg_CustomContextMenuAction,
@@ skipping 739 matching lines @@
 IPC_STRUCT_BEGIN(ViewHostMsg_BeginSmoothScroll_Params)
   IPC_STRUCT_MEMBER(bool, scroll_down)
   IPC_STRUCT_MEMBER(int, pixels_to_scroll)
   IPC_STRUCT_MEMBER(int, mouse_event_x)
   IPC_STRUCT_MEMBER(int, mouse_event_y)
 IPC_STRUCT_END()
 
 IPC_MESSAGE_ROUTED1(ViewHostMsg_BeginSmoothScroll,
                     ViewHostMsg_BeginSmoothScroll_Params /* params */)
 
+// Sent to initiate emulating device mode. In this mode, rendered image may be
+// not the same size as view itself. In response to this message, the host
+// generates a ViewMsg_EmulateDevice_ACK message.
+IPC_MESSAGE_ROUTED1(ViewHostMsg_EmulateDevice,
+                    bool /* enabled */)
+
 IPC_MESSAGE_ROUTED0(ViewHostMsg_Focus)
 IPC_MESSAGE_ROUTED0(ViewHostMsg_Blur)
 
 // Message sent from renderer to the browser when focus changes inside the
 // webpage. The parameter says whether the newly focused element needs
 // keyboard input (true for textfields, text areas and content editable divs).
 IPC_MESSAGE_ROUTED1(ViewHostMsg_FocusedNodeChanged,
     bool /* is_editable_node */)
 
 IPC_MESSAGE_ROUTED1(ViewHostMsg_SetCursor,
@@ skipping 706 matching lines @@
 // synchronously (see crbug.com/120597). This IPC message sends the character
 // bounds after every composition change to always have correct bound info.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_ImeCompositionRangeChanged,
                     ui::Range /* composition range */,
                     std::vector<gfx::Rect> /* character bounds */)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent ViewMsg, then ifdefs for platform specific ViewMsg, then platform
 // independent ViewHostMsg, then ifdefs for platform specific ViewHostMsg.