Pepper and WebKit API change to support a plugin knowing if a scrollbar is an overlay one.

ppapi/c/dev/ppb_scrollbar_dev.h

Index: ppapi/c/dev/ppb_scrollbar_dev.h
===================================================================
--- ppapi/c/dev/ppb_scrollbar_dev.h	(revision 95420)
+++ ppapi/c/dev/ppb_scrollbar_dev.h	(working copy)
@@ -21,15 +21,15 @@
 } PP_ScrollBy_Dev;
 PP_COMPILE_ASSERT_SIZE_IN_BYTES(PP_ScrollBy_Dev, 4);
 
-#define PPB_SCROLLBAR_DEV_INTERFACE_0_3 "PPB_Scrollbar(Dev);0.3"
-#define PPB_SCROLLBAR_DEV_INTERFACE_0_4 "PPB_Scrollbar(Dev);0.4"
-#define PPB_SCROLLBAR_DEV_INTERFACE PPB_SCROLLBAR_DEV_INTERFACE_0_4
+#define PPB_SCROLLBAR_DEV_INTERFACE_0_5 "PPB_Scrollbar(Dev);0.5"
+#define PPB_SCROLLBAR_DEV_INTERFACE PPB_SCROLLBAR_DEV_INTERFACE_0_5
 
 // The interface for a scrollbar.  A scrollbar is a widget, so the functions
 // in PPB_Widget can also be used with scrollbar objects.
-struct PPB_Scrollbar_0_4_Dev {
+struct PPB_Scrollbar_Dev {
   // Create a new scrollbar.  Returns 0 if the instance is invalid.
   PP_Resource (*Create)(PP_Instance instance,
+                        PP_Instance scrollbar_group,
                         PP_Bool vertical);
 
   // Returns PP_TRUE if the given resource is a Scrollbar. Returns PP_FALSE if
@@ -39,6 +39,9 @@
   // Gets the thickness of a scrollbar.
   uint32_t (*GetThickness)(PP_Resource resource);
 
+  // Returns PP_TRUE if the system scrollbar style is an overlap scrollbar.
+  PP_Bool (*IsOverlay)(PP_Resource scrollbar);
+
   // Get/set the value of the scrollbar.
   uint32_t (*GetValue)(PP_Resource scrollbar);
 
@@ -64,26 +67,5 @@
                    int32_t multiplier);
 };
 
-// Old version with no resource argument to GetThickness.
-struct PPB_Scrollbar_0_3_Dev {
-  PP_Resource (*Create)(PP_Instance instance,
-                        PP_Bool vertical);
-  PP_Bool (*IsScrollbar)(PP_Resource resource);
-  uint32_t (*GetThickness)();
-  uint32_t (*GetValue)(PP_Resource scrollbar);
-  void (*SetValue)(PP_Resource scrollbar,
-                   uint32_t value);
-  void (*SetDocumentSize)(PP_Resource scrollbar,
-                          uint32_t size);
-  void (*SetTickMarks)(PP_Resource scrollbar,
-                       const struct PP_Rect* tick_marks,
-                       uint32_t count);
-  void (*ScrollBy)(PP_Resource scrollbar,
-                   PP_ScrollBy_Dev unit,
-                   int32_t multiplier);
-};
-
-typedef struct PPB_Scrollbar_0_4_Dev PPB_Scrollbar_Dev;
-
 #endif  /* PPAPI_C_DEV_PPB_SCROLLBAR_DEV_H_ */