This is the exact same CL as in http://codereview.chromium.org/7570001 .

content/common/view_messages.h

Index: content/common/view_messages.h
diff --git a/content/common/view_messages.h b/content/common/view_messages.h
index 40222380e57edf82eadb01b1a510852cc27a54e6..eaf0655fc4ceb03683b95cd42a5d974b1c53c33c 100644
--- a/content/common/view_messages.h
+++ b/content/common/view_messages.h
@@ -923,6 +923,11 @@ IPC_MESSAGE_ROUTED1(ViewMsg_Replace,
 IPC_MESSAGE_ROUTED0(ViewMsg_Delete)
 IPC_MESSAGE_ROUTED0(ViewMsg_SelectAll)
 
+// Requests the renderer to select the region between two points.
+IPC_MESSAGE_ROUTED2(ViewMsg_SelectRange,
+                    gfx::Point /* start */,
+                    gfx::Point /* end */)
+
 // Copies the image at location x, y to the clipboard (if there indeed is an
 // image at that location).
 IPC_MESSAGE_ROUTED2(ViewMsg_CopyImageAt,
@@ -1711,9 +1716,11 @@ IPC_MESSAGE_ROUTED2(ViewHostMsg_SetTooltipText,
                     WebKit::WebTextDirection /* text direction hint */)
 
 // Notification that the text selection has changed.
-IPC_MESSAGE_ROUTED2(ViewHostMsg_SelectionChanged,
+IPC_MESSAGE_ROUTED4(ViewHostMsg_SelectionChanged,
                     std::string /* currently selected text */,
-                    ui::Range /* selection range */)
+                    ui::Range /* selection range */,
+                    gfx::Point,
+                    gfx::Point /* visual end points of selection */)
 
 // Asks the browser to display the file chooser.  The result is returned in a
 // ViewHost_RunFileChooserResponse message.