Eraser tool type plumbing from ui/events to web events and PPAPI.

ppapi/c/ppb_input_event.h

Index: ppapi/c/ppb_input_event.h
diff --git a/ppapi/c/ppb_input_event.h b/ppapi/c/ppb_input_event.h
index ca2bf152b9ddb65a662c2e5948cdbdf9c742d538..edf9c02ebc9c497235a6b9ec072fe943e09e4079 100644
--- a/ppapi/c/ppb_input_event.h
+++ b/ppapi/c/ppb_input_event.h
@@ -214,7 +214,9 @@ typedef enum {
   PP_INPUTEVENT_MODIFIER_CAPSLOCKKEY = 1 << 9,
   PP_INPUTEVENT_MODIFIER_NUMLOCKKEY = 1 << 10,
   PP_INPUTEVENT_MODIFIER_ISLEFT = 1 << 11,
-  PP_INPUTEVENT_MODIFIER_ISRIGHT = 1 << 12
+  PP_INPUTEVENT_MODIFIER_ISRIGHT = 1 << 12,
+  // PPAPI does not use modifiers 13 through 18.
+  PP_INPUTEVENT_MODIFIER_ISERASER = 1 << 19,
 } PP_InputEvent_Modifier;
 PP_COMPILE_ASSERT_SIZE_IN_BYTES(PP_InputEvent_Modifier, 4);
 
@@ -227,7 +229,8 @@ typedef enum {
   PP_INPUTEVENT_MOUSEBUTTON_NONE = -1,
   PP_INPUTEVENT_MOUSEBUTTON_LEFT = 0,
   PP_INPUTEVENT_MOUSEBUTTON_MIDDLE = 1,
-  PP_INPUTEVENT_MOUSEBUTTON_RIGHT = 2
+  PP_INPUTEVENT_MOUSEBUTTON_RIGHT = 2,
+  PP_INPUTEVENT_MOUSEBUTTON_ERASER = 3
 } PP_InputEvent_MouseButton;
 PP_COMPILE_ASSERT_SIZE_IN_BYTES(PP_InputEvent_MouseButton, 4);