Revert of Combine webrtc/api/java/android and webrtc/api/java/src. (patchset #1 id:1 of https://codereview.webrtc.org/2111823002/ )

Reason for revert:
Breaks downstream dependencies

Original issue's description:
> Combine webrtc/api/java/android and webrtc/api/java/src.
>
> It used to be that there was a Java api for devices not running Android
> but that is no longer the case. I combined the directories and made
> the folder structure chromium style.
>
> BUG=webrtc:6067
> R=magjed@webrtc.org, tommi@webrtc.org
>
> Committed: https://chromium.googlesource.com/external/webrtc/+/ceefe20dd65387d83059d9fc1ce84842650ed5e2

TBR=magjed@webrtc.org,tommi@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6067

Review URL: https://codereview.webrtc.org/2106333005 .

Cr-Commit-Position: refs/heads/master@{#13357}
diff --git a/webrtc/api/api.gyp b/webrtc/api/api.gyp
index eb8c9c0..3ab0bf9 100644
--- a/webrtc/api/api.gyp
+++ b/webrtc/api/api.gyp
@@ -35,27 +35,27 @@
             'libjingle_peerconnection',
           ],
           'sources': [
-            'android/jni/androidmediacodeccommon.h',
-            'android/jni/androidmediadecoder_jni.cc',
-            'android/jni/androidmediadecoder_jni.h',
-            'android/jni/androidmediaencoder_jni.cc',
-            'android/jni/androidmediaencoder_jni.h',
-            'android/jni/androidmetrics_jni.cc',
-            'android/jni/androidnetworkmonitor_jni.cc',
-            'android/jni/androidnetworkmonitor_jni.h',
-            'android/jni/androidvideocapturer_jni.cc',
-            'android/jni/androidvideocapturer_jni.h',
-            'android/jni/classreferenceholder.cc',
-            'android/jni/classreferenceholder.h',
-            'android/jni/jni_helpers.cc',
-            'android/jni/jni_helpers.h',
-            'android/jni/native_handle_impl.cc',
-            'android/jni/native_handle_impl.h',
-            'android/jni/peerconnection_jni.cc',
-            'android/jni/surfacetexturehelper_jni.cc',
-            'android/jni/surfacetexturehelper_jni.h',
             'androidvideocapturer.cc',
             'androidvideocapturer.h',
+            'java/jni/androidmediacodeccommon.h',
+            'java/jni/androidmediadecoder_jni.cc',
+            'java/jni/androidmediadecoder_jni.h',
+            'java/jni/androidmediaencoder_jni.cc',
+            'java/jni/androidmediaencoder_jni.h',
+            'java/jni/androidmetrics_jni.cc',
+            'java/jni/androidnetworkmonitor_jni.cc',
+            'java/jni/androidnetworkmonitor_jni.h',
+            'java/jni/androidvideocapturer_jni.cc',
+            'java/jni/androidvideocapturer_jni.h',
+            'java/jni/surfacetexturehelper_jni.cc',
+            'java/jni/surfacetexturehelper_jni.h',
+            'java/jni/classreferenceholder.cc',
+            'java/jni/classreferenceholder.h',
+            'java/jni/jni_helpers.cc',
+            'java/jni/jni_helpers.h',
+            'java/jni/native_handle_impl.cc',
+            'java/jni/native_handle_impl.h',
+            'java/jni/peerconnection_jni.cc',
           ],
           'include_dirs': [
             '<(libyuv_dir)/include',
@@ -83,7 +83,7 @@
             'libjingle_peerconnection_jni',
           ],
           'sources': [
-           'android/jni/jni_onload.cc',
+           'java/jni/jni_onload.cc',
           ],
           'variables': {
             # This library uses native JNI exports; tell GYP so that the