Update Robolectric SDK to 31

Update Robolectric SDK to 31

Bug: 206905117
Test: Manual
Change-Id: I918e3d29ecc7d853802a34bae0728fd737b9539b
diff --git a/robolectric_tests/Android.mk b/robolectric_tests/Android.mk
index 1117cc3..7d9b0e1 100644
--- a/robolectric_tests/Android.mk
+++ b/robolectric_tests/Android.mk
@@ -29,7 +29,7 @@
     mockito-robolectric-prebuilt \
     truth-prebuilt
 LOCAL_JAVA_LIBRARIES := \
-    platform-robolectric-3.6.2-prebuilt
+    platform-robolectric-4.5.1-prebuilt
 
 LOCAL_JAVA_RESOURCE_DIRS := config
 
diff --git a/robolectric_tests/config/robolectric.properties b/robolectric_tests/config/robolectric.properties
index 6a5d031..6c518c0 100644
--- a/robolectric_tests/config/robolectric.properties
+++ b/robolectric_tests/config/robolectric.properties
@@ -1,2 +1,2 @@
 manifest=packages/apps/ThemePicker/AndroidManifest.xml
-sdk=27
+sdk=31
diff --git a/robolectric_tests/robolectric_gradle_config/robolectric.properties b/robolectric_tests/robolectric_gradle_config/robolectric.properties
index 926e354..2916ca9 100644
--- a/robolectric_tests/robolectric_gradle_config/robolectric.properties
+++ b/robolectric_tests/robolectric_gradle_config/robolectric.properties
@@ -1,3 +1,3 @@
 # Do not include the manifest definition in this version
 # as it is specified directly in the gradle file
-sdk=27
\ No newline at end of file
+sdk=31
\ No newline at end of file