Tag TransportDIBs with the device scale factor they expect.

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 "content/common/content_export.h"
@@ skipping 516 matching lines @@
   //
   // If flags is zero, then this message corresponds to an unsolicited paint
   // request by the render view.  Any of the above bits may be set in flags,
   // which would indicate that this paint message is an ACK for multiple
   // request messages.
   IPC_STRUCT_MEMBER(int, flags)
 
   // Whether or not the renderer expects a ViewMsg_UpdateRect_ACK for this
   // update. True for 2D painting, but false for accelerated compositing.
   IPC_STRUCT_MEMBER(bool, needs_ack)
+
+  // All the above coordinates are in DIP. This is the scale factor needed

[Avi (use Gerrit), 2012/06/13 20:34:13]

DIBs or DIPs? Here it's DIPs.

[Nico, 2012/06/13 20:38:50]

This time it's right :-)

DIP is "device-independent pixel", which is how the aura code calls cocoa's view
units. DIB is "device-independent bitmap", which is (roughly) win32 lingo for a
bitmap.

+  // to convert them to pixels.
+  IPC_STRUCT_MEMBER(float, scale_factor)
 IPC_STRUCT_END()
 
 IPC_STRUCT_BEGIN(ViewMsg_PostMessage_Params)
   // The serialized script value.
   IPC_STRUCT_MEMBER(string16, data)
 
   // When sent to the browser, this is the routing ID of the source frame in
   // the source process.  The browser replaces it with the routing ID of the
   // equivalent (swapped out) frame in the destination process.  Set to
   // MSG_ROUTING_NONE if the source frame isn't supported (e.g., subframes).
@@ skipping 1546 matching lines @@
 // (according to the value of is_hung). The browser can give the user the
 // option of killing the plugin.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_PepperPluginHung,
                     int /* plugin_child_id */,
                     FilePath /* path */,
                     bool /* is_hung */)
 
 // Screen was rotated. Dispatched to the onorientationchange javascript API.
 IPC_MESSAGE_ROUTED1(ViewMsg_OrientationChangeEvent,
                     int /* orientation */)