Updating Blink-side WebGamepad interface

public/platform/WebGamepad.h

 // Copyright (C) 2011, 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:
 //
 // 1. Redistributions of source code must retain the above copyright
 //    notice, this list of conditions and the following disclaimer.
 // 2. Redistributions in binary form must reproduce the above copyright
 //    notice, this list of conditions and the following disclaimer in the
 //    documentation and/or other materials provided with the distribution.
@@ skipping 22 matching lines @@
 namespace blink {
 
 #pragma pack(push, 1)
 
 // This structure is intentionally POD and fixed size so that it can be shared
 // memory between hardware polling threads and the rest of the browser. See
 // also WebGamepads.h.
 class WebGamepad {
 public:
     static const size_t idLengthCap = 128;
+    static const size_t mappingLengthCap = 16;
     static const size_t axesLengthCap = 16;
     static const size_t buttonsLengthCap = 32;
 
     WebGamepad()
         : connected(false)
         , timestamp(0)
         , axesLength(0)
         , buttonsLength(0)
     {
         id[0] = 0;
+        mapping[0] = 0;
     }
 
     // Is there a gamepad connected at this index?
     bool connected;
 
     // Device identifier (based on manufacturer, model, etc.).
     WebUChar id[idLengthCap];
 
+    // Mapping type (for example "standard")
+    WebUChar mapping[mappingLengthCap];
+
     // Monotonically increasing value referring to when the data were last
     // updated.
     unsigned long long timestamp;
 
     // Number of valid entries in the axes array.
     unsigned axesLength;
 
     // Normalized values representing axes, in the range [-1..1].
     float axes[axesLengthCap];
 
     // Number of valid entries in the buttons array.
     unsigned buttonsLength;
 
-    // Normalized values representing buttons, in the range [0..1].
     float buttons[buttonsLengthCap];
 };
 
 #if BLINK_IMPLEMENTATION
-COMPILE_ASSERT(sizeof(WebGamepad) == 465, WebGamepad_has_wrong_size);
+COMPILE_ASSERT(sizeof(WebGamepad) == 497, WebGamepad_has_wrong_size);
 #endif
 
 #pragma pack(pop)
 
 }
 
 #endif // WebGamepad_h