Add template for chrome.hid documentation.

chrome/common/extensions/api/hid.idl

Index: chrome/common/extensions/api/hid.idl
diff --git a/chrome/common/extensions/api/hid.idl b/chrome/common/extensions/api/hid.idl
index 44bb857b525b7a6c69e749f02aa46e8a1f46efbd..a718ace3883f698d152a1c84534b938fe035aab9 100644
--- a/chrome/common/extensions/api/hid.idl
+++ b/chrome/common/extensions/api/hid.idl
@@ -6,10 +6,12 @@
 // This API provides access to HID operations from within the context of an app.
 // Using this API, apps can function as drivers for hardware devices.
 namespace hid {
-
-  // HID usage pair.
-  // |usage_page|: HID usage page.
-  // |usage|: HID usage.
+  // HID usage pair. Each enumerated device interface exposes an array of
+  // these objects. Values correspond to those defined by the
+  // <a href="http://www.usb.org/developers/devclass_docs/HID1_11.pdf>
+  // HID device class specification</a>.
+  // |usage_page|: HID usage page identifier.
+  // |usage|: Page-defined usage identifier.
   dictionary HidUsageAndPage {
     long usage_page;
     long usage;