Workaround java.gypi inclusion error in Chromium builds.

In order to switch Chromium to use WebRTC targets instead of
duplicated code listings in src/third_party/libjingle it must
be possible for Chromium to process webrtc/api/api.gyp. This is
currently not possible since it includes build/java.gypi, of which
the path is different in a Chromium checkout. It's not possible
to resolve this in another way since 'includes' processing takes
place early in the GYP cycle, before it's possible to use variables.
They're also processed ignoring conditional statements, resulting
in an error when api.gyp is processed.

BUG=webrtc:4256
TBR=perkj@webrtc.org
NOTRY=True

Review-Url: https://codereview.webrtc.org/2080563002
Cr-Commit-Position: refs/heads/master@{#13208}

webrtc/webrtc_examples.gyp

@@ -409,7 +409,7 @@
           'target_name': 'AppRTCDemo',
           'type': 'none',
           'dependencies': [
-            'api/api.gyp:libjingle_peerconnection_java',
+            'api/api_java.gyp:libjingle_peerconnection_java',
           ],
           'variables': {
             'apk_name': 'AppRTCDemo',