Android: Remove lint_suppressions_file

Follow-up to: https://crrev.com/c/2235463

Now that WebRTC is migrated to using invoker.lint_suppressions_file, we
no longer have a need for this global build override variable. Also
clarify that lint_suppressions_dep is specifically for generating this
custom file.

Bug: 1082743
Change-Id: Id6fd199aed8ad0007b192f022ccc9c152a058dea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2235943
Commit-Queue: Peter Wen <wnwen@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Auto-Submit: Peter Wen <wnwen@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776206}

build/config/android/internal_rules.gni

@@ -935,18 +935,16 @@ if (enable_java_templates) {
         }
       }
 
-      _suppressions_file = "//build/android/lint/suppressions.xml"
       if (defined(invoker.lint_suppressions_file)) {
         _suppressions_file = invoker.lint_suppressions_file
-      } else if (defined(lint_suppressions_file)) {
-        # DEPRECATED: Please specify invoker.lint_suppressions_file for apk
-        #     and app_bundle targets directly. This override will be removed
-        #     when WebRTC migrates to using invoker.lint_suppressions_file.
-        _suppressions_file = lint_suppressions_file
-      }
 
-      if (defined(invoker.lint_suppressions_dep)) {
-        deps += [ invoker.lint_suppressions_dep ]
+        # The custom suppressions file might be a generated file needing a dep.
+        # e.g. generating it by appending to the default suppressions.xml file.
+        if (defined(invoker.lint_suppressions_dep)) {
+          deps += [ invoker.lint_suppressions_dep ]
+        }
+      } else {
+        _suppressions_file = "//build/android/lint/suppressions.xml"
       }
 
       _min_sdk_version = default_min_sdk_version