Android: Fix a batch of @NullUnmarked suppressions

Also marks Map.remove() and Map.put() as @Nullable, which is required to
use their return values in assumeNonNull().

Bug: 389129271
Change-Id: Ib05618644f4bd1b63bc6cde00ae5ee82800d522a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6211297
Commit-Queue: Andrew Grieve <[email protected]>
Owners-Override: Andrew Grieve <[email protected]>
Reviewed-by: Mohamed Heikal <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1412943}
NOKEYCHECK=True
GitOrigin-RevId: 39e2175793634a0868e205685aec39b161f6996f
diff --git a/src/org/chromium/tools/errorprone/plugin/ChromeNullAwayLibraryModel.java b/src/org/chromium/tools/errorprone/plugin/ChromeNullAwayLibraryModel.java
index 5d65a85..32f4269 100644
--- a/src/org/chromium/tools/errorprone/plugin/ChromeNullAwayLibraryModel.java
+++ b/src/org/chromium/tools/errorprone/plugin/ChromeNullAwayLibraryModel.java
@@ -57,7 +57,9 @@
 
     @Override
     public ImmutableSet<MethodRef> nullableReturns() {
-        return ImmutableSet.of();
+        return ImmutableSet.of(
+                methodRef("java.util.Map", "put(K, V)"),
+                methodRef("java.util.Map", "remove(java.lang.Object)"));
     }
 
     @Override