Update Gamepad API to match the latest specification

ppapi/shared_impl/ppb_gamepad_shared.h

Index: ppapi/shared_impl/ppb_gamepad_shared.h
diff --git a/ppapi/shared_impl/ppb_gamepad_shared.h b/ppapi/shared_impl/ppb_gamepad_shared.h
index c6f535d3d14ecb97f9455624f3a468afc66104f2..32b5f1ff4eaa6e1aad250547ded7c45a9133f75e 100644
--- a/ppapi/shared_impl/ppb_gamepad_shared.h
+++ b/ppapi/shared_impl/ppb_gamepad_shared.h
@@ -9,6 +9,7 @@
 #include "base/strings/string16.h"
 #include "ppapi/c/ppb_gamepad.h"
 #include "ppapi/shared_impl/ppapi_shared_export.h"
+#include "third_party/WebKit/public/platform/WebGamepads.h"
 
 namespace ppapi {
 
@@ -19,7 +20,11 @@ namespace ppapi {
 
 struct WebKitGamepadButton {
   bool pressed;
+#if defined(ENABLE_NEW_GAMEPAD_API)
+  double value;
+#else
   float value;
+#endif
 };
 
 // This must match the definition of blink::Gamepad. The GamepadHost unit test
@@ -44,7 +49,11 @@ struct WebKitGamepad {
   unsigned axes_length;
 
   // Normalized values representing axes, in the range [-1..1].
+#if defined(ENABLE_NEW_GAMEPAD_API)
+  double axes[kAxesLengthCap];
+#else
   float axes[kAxesLengthCap];
+#endif
 
   // Number of valid entries in the buttons array.
   unsigned buttons_length;