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

ppapi/c/dev/ppb_scrollbar_dev.h

 /* Copyright (c) 2010 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef PPAPI_C_DEV_PPB_SCROLLBAR_DEV_H_
 #define PPAPI_C_DEV_PPB_SCROLLBAR_DEV_H_
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_macros.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_stdint.h"
 
 struct PP_Rect;
 
 typedef enum {
   PP_SCROLLBY_PIXEL = 0,
   PP_SCROLLBY_LINE = 1,
   PP_SCROLLBY_PAGE = 2,
   PP_SCROLLBY_DOCUMENT = 3
 } 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_0_5_Dev {
   // Create a new scrollbar.  Returns 0 if the instance is invalid.
   PP_Resource (*Create)(PP_Instance instance,
                         PP_Bool vertical);
 
   // Returns PP_TRUE if the given resource is a Scrollbar. Returns PP_FALSE if
   // the resource is invalid or some type other than a scrollbar.
   PP_Bool (*IsScrollbar)(PP_Resource resource);
 
   // 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);
 
   void (*SetValue)(PP_Resource scrollbar,
                    uint32_t value);
 
   // Set the document size (i.e. total length of the region that's being
   // scrolled).
   void (*SetDocumentSize)(PP_Resource scrollbar,
                           uint32_t size);
 
   // Updates the tickmarks.  Only valid for vertical scrollbars.  "tick_marks"
   // contains "count" PP_Rect objects.
   void (*SetTickMarks)(PP_Resource scrollbar,
                        const struct PP_Rect* tick_marks,
                        uint32_t count);
 
   // Scroll by "multiplier" pixels/lines/pages units.  Positive values are
   // forward and negative are backward.  If "unit" is document then any positive
   // value goes to the end while any negative value goes to the beginning.
   void (*ScrollBy)(PP_Resource scrollbar,
                    PP_ScrollBy_Dev unit,
                    int32_t multiplier);
 };
 
+// Old version without IsOverlay.
+struct PPB_Scrollbar_0_4_Dev {
+  PP_Resource (*Create)(PP_Instance instance,
+                        PP_Bool vertical);
+  PP_Bool (*IsScrollbar)(PP_Resource resource);
+  uint32_t (*GetThickness)(PP_Resource resource);
+  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);
+};
+
 // 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;
+typedef struct PPB_Scrollbar_0_5_Dev PPB_Scrollbar_Dev;
 
 #endif  /* PPAPI_C_DEV_PPB_SCROLLBAR_DEV_H_ */
-