jni_generator: Fix native method capitalization for Proxy Natives.

Was already done for native functions but missed when calling native
instance methods.

Bug: 934847
Change-Id: Ie4bfbe81c748d8f3c78de77cd759ff4d2c804791
Reviewed-on: https://chromium-review.googlesource.com/c/1495443
Auto-Submit: Eric Stevenson <estevenson@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Commit-Queue: Tommy Nyquist <nyquist@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636561}
5 files changed