Implement disambiguation popup

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 aad8ed96fac6ab2f62727da0eae195616b186918..0cf8bd444bfc3380015928b2e50dc86923a217dd 100644
--- a/content/common/view_messages.h
+++ b/content/common/view_messages.h
@@ -1445,6 +1445,11 @@ IPC_MESSAGE_ROUTED1(ViewMsg_SelectPopupMenuItem,
                     int /* selected index, -1 means no selection */)
 #endif
 
+// An acknowledge to ViewHostMsg_MultipleTargetsTouched to notify the renderer
+// process to release the magnified image.
+IPC_MESSAGE_ROUTED1(ViewMsg_ReleaseDisambiguationPopupDIB,
+                    TransportDIB::Handle /* DIB handle */)
+
 // -----------------------------------------------------------------------------
 // Messages sent from the renderer to the browser.
 
@@ -2479,3 +2484,10 @@ IPC_MESSAGE_ROUTED2(ViewHostMsg_MediaPlayerSeek,
 IPC_MESSAGE_ROUTED1(ViewHostMsg_MediaPlayerStart,
                     int /* player_id */)
 #endif
+
+// Notifies that multiple touch targets may have been pressed, and to show
+// the disambiguation popup.
+IPC_MESSAGE_ROUTED3(ViewHostMsg_ShowDisambiguationPopup,
+                    gfx::Rect, /* Border of touched targets */
+                    gfx::Size, /* Size of zoomed image */
+                    TransportDIB::Id /* DIB of zoomed image */)