Updating Blink-side WebGamepad interface

public/platform/WebGamepad.h

Index: public/platform/WebGamepad.h
diff --git a/public/platform/WebGamepad.h b/public/platform/WebGamepad.h
index 93df8a28b67adaa5022aa13843b26a0908fe5a67..f2bd49d17c93aa7385a23a5dabfba7ca48358117 100644
--- a/public/platform/WebGamepad.h
+++ b/public/platform/WebGamepad.h
@@ -40,6 +40,7 @@ namespace blink {
 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;
 
@@ -50,6 +51,7 @@ public:
         , buttonsLength(0)
     {
         id[0] = 0;
+        mapping[0] = 0;
     }
 
     // Is there a gamepad connected at this index?
@@ -58,6 +60,9 @@ public:
     // 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;
@@ -71,12 +76,11 @@ public:
     // 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)