Introduces Android API level linting, fixes all current API lint errors.

talk/libjingle.gyp

Index: talk/libjingle.gyp
diff --git a/talk/libjingle.gyp b/talk/libjingle.gyp
index cd5385c11fd30067ebde77a3ee7b4aa760364f40..dfc0d5d518fe4475665a13863d5eb82f5c0ddb28 100755
--- a/talk/libjingle.gyp
+++ b/talk/libjingle.gyp
@@ -227,6 +227,12 @@
             'libjingle_peerconnection_so',
           ],
           'variables': {
+            # Designate as Chromium code and point to our lint settings to
+            # enable linting of the WebRTC code (this is the only way to make
+            # lint_action invoke the Android linter).
+            'android_manifest_path': 'app/webrtc/java/lint/AndroidManifest.xml',
+            'suppressions_file': 'app/webrtc/java/lint/suppressions.xml',
+            'chromium_code': 1,

[kjellander_webrtc, 2015/11/12 13:02:18]

I'd like us to do this for more Android Java targets in WebRTC, but that can be
done in a follow-up CL.

[phoglund, 2015/11/12 13:21:34]

This covers all our java production code I think, but yeah, if we find more
targets we can sure add those.

             'java_in_dir': 'app/webrtc/java',
             'webrtc_base_dir': '<(webrtc_root)/base',
             'webrtc_modules_dir': '<(webrtc_root)/modules',