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

third_party/WebKit/Source/WebKit/chromium/public/WebScrollbar.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 16 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WebScrollbar_h
 #define WebScrollbar_h
 
 #include "WebCanvas.h"
 #include "WebCommon.h"
 
+// TODO(jam): take this out once Chrome rolls this revision of WebKit.
+#define WEBSCROLLBAR_SUPPORTS_OVERLAY
+
 namespace WebKit {
 
 class WebInputEvent;
+class WebPluginContainer;
 class WebScrollbarClient;
 struct WebRect;
 
 class WebScrollbar {
 public:
     enum Orientation {
         Horizontal,
         Vertical
     };
 
     enum ScrollDirection {
         ScrollBackward,
         ScrollForward
     };
 
     enum ScrollGranularity {
         ScrollByLine,
         ScrollByPage,
         ScrollByDocument,
         ScrollByPixel
     };
 
-    // Creates a WebScrollbar.
-    WEBKIT_EXPORT static WebScrollbar* create(WebScrollbarClient*, Orientation);
+    // Creates a WebScrollbar for use by a plugin. The plugin container and
+    // client are guaranteed to outlive this object.
+    WEBKIT_EXPORT static WebScrollbar* create(Orientation,

[darin (slow to review), 2011/08/10 18:00:34]

nit: Let's call this createForPlugin just to be a bit more self-documenting.

+                                              WebPluginContainer*,
+                                              WebScrollbarClient*);
 
     virtual ~WebScrollbar() {}
 
     // Gets the thickness of the scrollbar in pixels.
     WEBKIT_EXPORT static int defaultThickness();
 
+    // Return true if this is an overlay scrollbar.
+    virtual bool isOverlay() = 0;

[darin (slow to review), 2011/08/10 18:00:34]

can this be a const method?  (like value())

+
     // Sets the rectangle of the scrollbar.
     virtual void setLocation(const WebRect&) = 0;
 
     // Gets the current value (i.e. position inside the region).
     virtual int value() const = 0;
 
     // Sets the current value.
     virtual void setValue(int position) = 0;
 
     // Sets the size of the scrollable region in pixels.  i.e. if a document is
     // 800x10000 pixels and the viewport is 1000x1000 pixels, then setLocation
     // for the vertical scrollbar would have passed in a rectangle like:
     //            (800 - defaultThickness(), 0) (defaultThickness() x 10000)
     // and setDocumentSize(10000)
     virtual void setDocumentSize(int size) = 0;
 
     // Scroll back or forward with the given granularity.
     virtual void scroll(ScrollDirection, ScrollGranularity, float multiplier) = 0;
 
     // Paint the given rectangle.
     virtual void paint(WebCanvas*, const WebRect&) = 0;
 
     // Returns true iff the given event was used.
     virtual bool handleInputEvent(const WebInputEvent&) = 0;
 };
 
 } // namespace WebKit
 
 #endif