Android: presubmit check against IS_DESKTOP_ANDROID

No change to production behavior. This adds a presubmit check for
IS_DESKTOP_ANDROID. The goal is to confine use of this value to chrome/
layer and other higher layers, but to ban this in content/ layer and
below.

This has "warning" status only so that it can be bypassed in case of
false positive, however the intention is that generally
IS_DESKTOP_ANDROID should only live in higher layers.

Fixed: 401628399
Test: vpython3 PRESUBMIT_test.py
Change-Id: Ice010be105a476100acf5cf70a3d262228916c33
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6336803
Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1431159}

PRESUBMIT.py

@@ -299,6 +299,24 @@ _BANNED_JAVA_FUNCTIONS : Sequence[BanRule] = (
          ' for more details and suggested replacements.', ),
         False,
     ),
+    BanRule(
+        pattern=(r'IS_DESKTOP_ANDROID'),
+        explanation=(
+            'Features which depend on IS_DESKTOP_ANDROID should only exist in '
+            'chrome/ layer and similar layers. Lower layers such as content/ '
+            'should not have features which are only designed for '
+            'desktop-android builds. See https://crbug.com/401628399.', ),
+        treat_as_error=False,
+        excluded_paths=[
+          _THIRD_PARTY_EXCEPT_BLINK, # Don't warn in third_party folders.
+          r'^build/', # This is permitted in build/ folder.
+          r'^chrome/', # This is permitted in chrome/ folder.
+          r'^components/', # This is permitted only for components/ that are not shared by WebView.
+          r'^extensions/', # This is permitted in chrome/ folder.
+          r'^infra/', # This is permitted in infra/ folder.
+          r'^tools/', # This is permitted in tools/ folder.
+        ],
+    ),
 )
 
 _BANNED_JAVASCRIPT_FUNCTIONS : Sequence [BanRule] = (
@@ -2163,6 +2181,24 @@ _BANNED_CPP_FUNCTIONS: Sequence[BanRule] = (
             'See https://crbug.com/40485510 for more details.', ),
         treat_as_error=False,
     ),
+    BanRule(
+        pattern=(r'IS_DESKTOP_ANDROID'),
+        explanation=(
+            'Features which depend on IS_DESKTOP_ANDROID should only exist in '
+            'chrome/ layer and similar layers. Lower layers such as content/ '
+            'should not have features which are only designed for '
+            'desktop-android builds. See https://crbug.com/401628399.', ),
+        treat_as_error=False,
+        excluded_paths=[
+          _THIRD_PARTY_EXCEPT_BLINK, # Don't warn in third_party folders.
+          r'^build/', # This is permitted in build/ folder.
+          r'^chrome/', # This is permitted in chrome/ folder.
+          r'^components/', # This is permitted only for components/ that are not shared by WebView.
+          r'^extensions/', # This is permitted in chrome/ folder.
+          r'^infra/', # This is permitted in infra/ folder.
+          r'^tools/', # This is permitted in tools/ folder.
+        ],
+    ),
 )
 
 _DEPRECATED_SYNC_CONSENT_FUNCTION_WARNING = (

PRESUBMIT_test.py

@@ -2972,6 +2972,10 @@ class BannedTypeCheckTest(unittest.TestCase):
                 'some/java/problematic/accessibilityTypeAnnouncement.java', [
                     'accessibilityEvent.setEventType(AccessibilityEvent.TYPE_ANNOUNCEMENT);'
                 ]),
+            MockFile(
+                'content/java/problematic/desktopandroid.java', [
+                    'if (BuildConfig.IS_DESKTOP_ANDROID) {}'
+                ]),
         ]
 
         errors = PRESUBMIT.CheckNoBannedFunctions(input_api, MockOutputApi())
@@ -3001,6 +3005,9 @@ class BannedTypeCheckTest(unittest.TestCase):
         self.assertTrue(
             'some/java/problematic/accessibilityTypeAnnouncement.java' in
             errors[0].message)
+        self.assertTrue(
+            'content/java/problematic/desktopandroid.java' in
+            errors[0].message)
 
 
     def testBannedCppFunctions(self):
@@ -3029,6 +3036,8 @@ class BannedTypeCheckTest(unittest.TestCase):
             MockFile('banned_ranges_usage.cc',
                      ['std::ranges::subrange(first, last)']),
             MockFile('views_usage.cc', ['std::views::all(vec)']),
+            MockFile('content/desktop_android.cc',
+                     ['#if BUILDFLAG(IS_DESKTOP_ANDROID)']),
         ]
 
         results = PRESUBMIT.CheckNoBannedFunctions(input_api, MockOutputApi())
@@ -3051,6 +3060,7 @@ class BannedTypeCheckTest(unittest.TestCase):
         self.assertFalse('allowed_ranges_usage.cc' in results[1].message)
         self.assertTrue('banned_ranges_usage.cc' in results[1].message)
         self.assertTrue('views_usage.cc' in results[1].message)
+        self.assertTrue('content/desktop_android.cc' in results[0].message)
 
     def testBannedCppRandomFunctions(self):
         banned_rngs = [