Reland "Android: Add Error Prone warning against Java stream() apis"

This reverts commit 8ff33dbc1d.

Reason for reland: Internal fix landed

Original change's description:
> Revert "Android: Add Error Prone warning against Java stream() apis"
>
> This reverts commit e910d272c0.
>
> Reason for revert: crbug.com/344943957#comment13
>
> Original change's description:
> > Android: Add Error Prone warning against Java stream() apis
> >
> > And minor clarifying tweaks to style guide wrt streams
> >
> > Bug: 344943957
> > Change-Id: I90b976866c8f3f71826459b7d3097692e1f533b4
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6042674
> > Auto-Submit: Andrew Grieve <agrieve@chromium.org>
> > Commit-Queue: Andrew Grieve <agrieve@chromium.org>
> > Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#1388426}
>
> Bug: 344943957
> Change-Id: Ib9b3d8db9f47383eaced5192a15e7cac6427da35
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6051419
> Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
> Auto-Submit: Keigo Oka <oka@chromium.org>
> Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Reviewed-by: Andrew Grieve <agrieve@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1388467}

Bug: 344943957
Change-Id: I6668c182aa455972684e6863925c498f494fd11f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6055458
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1389041}

build/android/gyp/compile_java.py

@@ -38,6 +38,8 @@ ERRORPRONE_CHECKS_TO_APPLY = []
 TESTONLY_ERRORPRONE_WARNINGS_TO_DISABLE = [
     # Too much effort to enable.
     'UnusedVariable',
+    # These are allowed in tests.
+    'NoStreams',
 ]
 
 # Full list of checks: https://errorprone.info/bugpatterns
@@ -148,6 +150,7 @@ ERRORPRONE_WARNINGS_TO_ENABLE = [
     'UnnecessaryStaticImport',
     'UseBinds',
     'WildcardImport',
+    'NoStreams',
 ]
 
 
@@ -354,6 +357,7 @@ def _OnStaleMd5(changes, options, javac_cmd, javac_args, java_files, kt_files):
           stamp_file=options.jar_path,
           force=options.use_build_server,
           experimental=options.experimental_build_server)):
+    logging.info('Using build server')
     return
 
   if options.enable_kythe_annotations:

chrome/browser/tabmodel/android/java/src/org/chromium/chrome/browser/tabmodel/TabGroup.java

@@ -105,6 +105,7 @@ class TabGroup {
     }
 
     /** Returns the ID of the last tab in the group. */
+    @SuppressWarnings("NoStreams") // No better way to do this while using LinkedHashSet.
     int getTabIdOfLastTab() {
         return mTabIds.stream().skip(mTabIds.size() - 1).findFirst().get();
     }

styleguide/java/java.md

@@ -261,16 +261,32 @@ Log.d(TAG, "There are %d cats", countCats());  // countCats() not stripped.
 
 ### Streams
 
-Most uses of [Java streams] are discouraged. If you can write your code as an
-explicit loop, then do so. The primary reason for this guidance is because the
-lambdas (and method references) needed for streams almost always result in
-larger binary size ([example](https://chromium-review.googlesource.com/c/chromium/src/+/4329952).
+Using [Java streams] outside of tests is strongly discouraged. If you can write
+your code as an explicit loop, then do so. The primary reason for this guidance
+is because the lambdas and method references needed for streams almost always
+result in larger binary size than their loop equivalents (see
+[crbug.com/344943957] for examples).
 
 The `parallel()` and `parallelStream()` APIs are simpler than their loop
-equivalents, but are are currently banned due to a lack of a compelling use case
-in Chrome. If you find one, please discuss on `java@chromium.org`.
+equivalents, but are banned due to a lack of a compelling use case in Chrome.
+If you find one, please discuss on `java@chromium.org`.
+
+Use of `stream()` without a lambda / method reference is allowed. E.g.:
+
+```java
+@SuppressWarnings("NoStreams")
+private static List<Integer> boxInts(int[] arr) {
+    return Arrays.stream(arr).boxed().collect(Collectors.toList());
+}
+
+@SuppressWarnings("NoStreams")
+private static List<String> readLines(BufferedReader bufferedReader) {
+    return bufferedReader.lines().collect(Collectors.toList());
+}
+```
 
 [Java streams]: https://docs.oracle.com/javase/8/docs/api/java/util/stream/package-summary.html
+[crbug.com/344943957]: https://crbug.com/344943957
 
 ### AndroidX Annotations {#annotations}
 

tools/android/errorprone_plugin/BUILD.gn

@@ -17,6 +17,7 @@ java_binary("errorprone_plugin") {
     "src/org/chromium/tools/errorprone/plugin/NoDynamicStringsInTraceEventCheck.java",
     "src/org/chromium/tools/errorprone/plugin/NoRedundantFieldInitCheck.java",
     "src/org/chromium/tools/errorprone/plugin/NoResourcesGetColor.java",
+    "src/org/chromium/tools/errorprone/plugin/NoStreams.java",
     "src/org/chromium/tools/errorprone/plugin/NoSynchronizedMethodCheck.java",
     "src/org/chromium/tools/errorprone/plugin/NoSynchronizedThisCheck.java",
     "src/org/chromium/tools/errorprone/plugin/TestClassNameCheck.java",

tools/android/errorprone_plugin/OWNERS

@@ -1,3 +1,2 @@
-agrieve@chromium.org
+file://build/android/OWNERS
 nyquist@chromium.org
-wnwen@chromium.org

tools/android/errorprone_plugin/src/org/chromium/tools/errorprone/plugin/NoStreams.java

@@ -0,0 +1,43 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.tools.errorprone.plugin;
+
+import static com.google.errorprone.matchers.Matchers.instanceMethod;
+
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.predicates.TypePredicates;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+
+import org.chromium.build.annotations.ServiceImpl;
+
+/** Checks for calls to .stream(). See //styleguide/java/java.md for rationale. */
+@ServiceImpl(BugChecker.class)
+@BugPattern(
+        name = "NoStreams",
+        summary = "Prefer loops over stream().",
+        severity = BugPattern.SeverityLevel.WARNING,
+        linkType = BugPattern.LinkType.CUSTOM,
+        link =
+                "https://chromium.googlesource.com/chromium/src/+/main/styleguide/java/java.md#Streams")
+public class NoStreams extends BugChecker implements BugChecker.MethodInvocationTreeMatcher {
+    private static final Matcher<ExpressionTree> MATCHER =
+            instanceMethod().onClass(TypePredicates.isDescendantOf("java.util.stream.Stream"));
+
+    @Override
+    public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState visitorState) {
+        if (!MATCHER.matches(tree, visitorState)) {
+            return Description.NO_MATCH;
+        }
+
+        return buildDescription(tree)
+                .setMessage("Using Java stream APIs is strongly discouraged. Use loops instead.")
+                .build();
+    }
+}