Make stylus's eraser button work on Mac

content/browser/renderer_host/render_widget_host_view_mac.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 #include <IOSurface/IOSurface.h>
 #include <stddef.h>
@@ skipping 182 matching lines @@
 - (void)setOpaque:(BOOL)opaque;
 // True for always-on-top special windows (e.g. Balloons and Panels).
 - (BOOL)acceptsMouseEventsWhenInactive;
 // Cancel ongoing composition (abandon the marked text).
 - (void)cancelComposition;
 // Confirm ongoing composition.
 - (void)finishComposingText;
 - (void)updateCursor:(NSCursor*)cursor;
 - (NSRect)firstViewRectForCharacterRange:(NSRange)theRange
                              actualRange:(NSRangePointer)actualRange;
+- (void)tabletEvent:(NSEvent*)theEvent;
 - (void)quickLookWithEvent:(NSEvent*)event;
 - (void)showLookUpDictionaryOverlayAtPoint:(NSPoint)point;
 - (void)showLookUpDictionaryOverlayFromRange:(NSRange)range
                                   targetView:(NSView*)targetView;
 @end
 
 namespace content {
 
 ///////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewMac
@@ skipping 342 matching lines @@
 
   // Factory used to safely scope delayed calls to ShutdownHost().
   base::WeakPtrFactory<RenderWidgetHostViewMac> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_