Revert "Save 166 KB of per-process private data by deleting 'const'"

This reverts commit 7a0168cc now that we
don't need to work around the VC++ bug.

Bug: 934323
Change-Id: I594c2c6b86096ffc8643e0f9ceb5b357e1c214be
Reviewed-on: https://chromium-review.googlesource.com/c/1484353
Auto-Submit: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: Jun Cai <juncai@chromium.org>
Reviewed-by: Jun Cai <juncai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635224}

device/usb/usb_ids.h

@@ -13,14 +13,14 @@
 namespace device {
 
 struct UsbProduct {
-  uint16_t id;
+  const uint16_t id;
   const char* name;
 };
 
 struct UsbVendor {
-  uint16_t id;
+  const uint16_t id;
   const char* name;
-  size_t product_size;
+  const size_t product_size;
   const UsbProduct* products;
 };