Fix generation of Android SampleApp APK now that we default to using gyp's ninja generator.

platform_tools/android/gyp/skia_android.gypi

 {
   'targets': [
     {
       'target_name': 'CopySampleAppDeps',
       'type': 'none',
       'dependencies': [
         'skia_lib.gyp:skia_lib',
         'SampleApp.gyp:SampleApp',
       ],
       'variables': {
@@ skipping 40 matching lines @@
         '../launcher/skia_launcher.cpp',
       ],
     },
     {
       'target_name': 'SampleApp_APK',
       'type': 'none',
       'dependencies': [
         'CopySampleAppDeps',
       ],
       'variables': {
-         'ANDROID_SDK_ROOT': '<!(echo $ANDROID_SDK_ROOT)'
+         'ANDROID_SDK_ROOT': '<!(echo $ANDROID_SDK_ROOT)',
+         # the ninja generator treats PRODUCT_DIR as a relative path to the
+         # gyp directory but android ant build wants a path relative to the
+         # build.xml file so we do that adjustment here. 
+         'ANDROID_OUT': '../../<(PRODUCT_DIR)/android'
        },
       'actions': [
         {
           'action_name': 'SkiaAndroid_apk',
           'inputs': [
             '<(android_base)/app/AndroidManifest.xml',
             '<(android_base)/app/build.xml',
             '<(android_base)/app/project.properties',
             '<(android_base)/app/jni/com_skia_SkiaSampleRenderer.h',
             '<(android_base)/app/jni/com_skia_SkiaSampleRenderer.cpp',
             '<(android_base)/app/src/com/skia/SkiaSampleActivity.java',
             '<(android_base)/app/src/com/skia/SkiaSampleRenderer.java',
             '<(android_base)/app/src/com/skia/SkiaSampleView.java',
           ],
           'outputs': [
             '<(PRODUCT_DIR)/../android/bin/SkiaAndroid.apk',
           ],
           'action': [
             'ant',
             '-quiet',
             '-f',
             '<(android_base)/app/build.xml',
-            '-Dout.dir=<(PRODUCT_DIR)/android/bin',
-            '-Dgen.absolute.dir=<(PRODUCT_DIR)/android/gen',
-            '-Dnative.libs.absolute.dir=<(PRODUCT_DIR)/android/libs',
-            '-Dout.final.file=<(PRODUCT_DIR)/android/bin/SkiaAndroid.apk',
+            '-Dout.dir=<(ANDROID_OUT)/bin',
+            '-Dgen.absolute.dir=<(ANDROID_OUT)/gen',
+            '-Dnative.libs.absolute.dir=<(ANDROID_OUT)/libs',
+            '-Dout.final.file=<(ANDROID_OUT)/bin/SkiaAndroid.apk',
             '-Dsdk.dir=<(ANDROID_SDK_ROOT)',
             'debug',
           ],
         },
       ],
     },
   ],
 }