Mass refactoring: Change JNI #includes to use full paths (webrtc/).

Using relative paths for JNI includes is causing build failures in chromium.

WebRTC already uses full include paths for generated JNI headers, so this CL
just removes the "jni_package" parameter from WebRTC generate_jni() targets
and removes the "jni/" portion of includes. The "jni_package" variable will be
removed from the generate_jni() template shortly.

To fix includes:
find . -name *.cc -exec sed -i -E 's@(#include.+generated.+jni)/jni/(.+_jni.h)@\1/\2@' {} \;

See https://groups.google.com/a/chromium.org/forum/?#!topic/java/MEovGrAwbqI
for discussion on naming scheme.

No-Try: True
TBR: kwiberg@webrtc.org
Bug: chromium:964169
Change-Id: I758c1b41bf6f5005587e55b82f14065fe251baad
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/143521
Commit-Queue: Oleh Prypin <oprypin@webrtc.org>
Reviewed-by: Oleh Prypin <oprypin@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28380}
diff --git a/sdk/android/native_unittests/application_context_provider.cc b/sdk/android/native_unittests/application_context_provider.cc
index 885856e..07b3c04 100644
--- a/sdk/android/native_unittests/application_context_provider.cc
+++ b/sdk/android/native_unittests/application_context_provider.cc
@@ -9,7 +9,7 @@
  */
 #include "sdk/android/native_unittests/application_context_provider.h"
 
-#include "sdk/android/generated_native_unittests_jni/jni/ApplicationContextProvider_jni.h"
+#include "sdk/android/generated_native_unittests_jni/ApplicationContextProvider_jni.h"
 #include "sdk/android/src/jni/jni_helpers.h"
 
 namespace webrtc {