Update Gamepad API to match the latest specification

ppapi/c/ppb_gamepad.h

Index: ppapi/c/ppb_gamepad.h
diff --git a/ppapi/c/ppb_gamepad.h b/ppapi/c/ppb_gamepad.h
index 4beb9b8f1f8599bdc5e720d47633670f16564d9f..3c36acec50dba6c4445531d1f1fe515975075835 100644
--- a/ppapi/c/ppb_gamepad.h
+++ b/ppapi/c/ppb_gamepad.h
@@ -39,7 +39,7 @@ struct PP_GamepadSampleData {
    * Normalized values for the axes, indices valid up to |axes_length|-1. Axis
    * values range from -1..1, and are in order of "importance".
    */
-  float axes[16];
+  double axes[16];
   /**
    * Number of valid elements in the |buttons| array.
    */
@@ -48,7 +48,7 @@ struct PP_GamepadSampleData {
    * Normalized values for the buttons, indices valid up to |buttons_length|
    * - 1. Button values range from 0..1, and are in order of importance.
    */
-  float buttons[32];
+  double buttons[32];
   /**
    * Monotonically increasing value that is incremented when the data have
    * been updated.
@@ -66,7 +66,7 @@ struct PP_GamepadSampleData {
   /* Padding to make the struct the same size between 64 and 32. */
   char unused_pad_[4];
 };
-PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_GamepadSampleData, 472);
+PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_GamepadSampleData, 672);
 
 /**
  * The data for all gamepads connected to the system.
@@ -83,7 +83,7 @@ struct PP_GamepadsSampleData {
    */
   struct PP_GamepadSampleData items[4];
 };
-PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_GamepadsSampleData, 1896);
+PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_GamepadsSampleData, 2696);
 /**
  * @}
  */