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 f0c1bd7a46842fa9c08aa858f32ef90abc20065a..a9ec6581ba72980ad6618098bfa40d3bbc4a886e 100644
--- a/content/common/view_messages.h
+++ b/content/common/view_messages.h
@@ -1360,6 +1360,11 @@ IPC_MESSAGE_CONTROL1(ViewMsg_TempCrashWithData,
 IPC_MESSAGE_ROUTED1(ViewMsg_SetAccessibilityMode,
                     AccessibilityMode)
 
+// 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.
 
@@ -2280,3 +2285,10 @@ IPC_MESSAGE_ROUTED1(ViewMsg_OrientationChangeEvent,
 // the names of any frames.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_FrameTreeUpdated,
                     std::string /* json encoded frame tree */)
+
+// 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 */)