Update Gamepad.axes / GamepadButton.value to match the latest specification

public/platform/WebGamepad.h

Index: public/platform/WebGamepad.h
diff --git a/public/platform/WebGamepad.h b/public/platform/WebGamepad.h
index b2f32da02f57a3a4ef1a03469f14e541e29605d3..463bb17e16bd0b36a99c51fadba4b65644fa2711 100644
--- a/public/platform/WebGamepad.h
+++ b/public/platform/WebGamepad.h
@@ -38,16 +38,29 @@ class WebGamepadButton {
 public:
     WebGamepadButton()
         : pressed(false)
+// FIXME(cdumez): Remove #ifdefs once chromium-side has been updated.
+#if defined(ENABLE_NEW_GAMEPAD_API)
+        , value(0.)
+#else
         , value(0.f)
+#endif
     {
     }
+#if defined(ENABLE_NEW_GAMEPAD_API)
+    WebGamepadButton(bool pressed, double value)
+#else
     WebGamepadButton(bool pressed, float value)
+#endif
         : pressed(pressed)
         , value(value)
     {
     }
     bool pressed;
+#if defined(ENABLE_NEW_GAMEPAD_API)
+    double value;
+#else
     float value;
+#endif
 };
 
 // This structure is intentionally POD and fixed size so that it can be shared
@@ -84,7 +97,11 @@ public:
     unsigned axesLength;
 
     // Normalized values representing axes, in the range [-1..1].
+#if defined(ENABLE_NEW_GAMEPAD_API)
+    double axes[axesLengthCap];
+#else
     float axes[axesLengthCap];
+#endif
 
     // Number of valid entries in the buttons array.
     unsigned buttonsLength;
@@ -97,8 +114,12 @@ public:
 };
 
 #if BLINK_IMPLEMENTATION
+#if defined(ENABLE_NEW_GAMEPAD_API)
+COMPILE_ASSERT(sizeof(WebGamepad) == 721, WebGamepad_has_wrong_size);
+#else
 COMPILE_ASSERT(sizeof(WebGamepad) == 529, WebGamepad_has_wrong_size);
 #endif
+#endif
 
 #pragma pack(pop)