Extend presubmit _CheckUniquePtr to multiline

The presubmit check _CheckUniquePtr guards against calling
std::unique_ptr constructor directly, instead directing code authors to
use std::make_unique.

This check currently fails to match multiline expressions. While it
catches
bar = std::unique_ptr<T>(foo);
it does not catch
bar =
    std::unique_ptr<T>(foo);
nor does it catch
bar = std::unique_ptr<T>(
    foo);

This CL fixes it by extending the match pattern to catch all lines with
the substring "std::unique_ptr<T>(". (But not those with
"std::unique_ptr<T>()", which should be handled by the "nullptr-check".)

Bug: 827961
Change-Id: I376b5e9811418205e294e97de0b6b7bcbf6891d2
Reviewed-on: https://chromium-review.googlesource.com/989735
Commit-Queue: Vaclav Brozek <vabr@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548045}

PRESUBMIT.py

@@ -1586,7 +1586,7 @@ def _CheckUniquePtr(input_api, output_api):
                   input_api.DEFAULT_BLACK_LIST),
       white_list=(file_inclusion_pattern,))
   return_construct_pattern = input_api.re.compile(
-      r'(=|\breturn)\s*std::unique_ptr<.*?(?<!])>\([^)]+\)')
+      r'(=|\breturn|^)\s*std::unique_ptr<.*?(?<!])>\(([^)]|$)')
   null_construct_pattern = input_api.re.compile(
       r'\b(?<!<)std::unique_ptr<[^>]*>([^(<]*>)?\(\)')
   errors = []

PRESUBMIT_test.py

@@ -1646,21 +1646,31 @@ def testTruePositives(self):
       MockFile('dir/java/src/bar.mm', ['bar = std::unique_ptr<T>(foo)']),
       MockFile('dir/java/src/baz.cc', ['std::unique_ptr<T>()']),
       MockFile('dir/java/src/baz-p.cc', ['std::unique_ptr<T<P>>()']),
-      # TODO(crbug.com/827961) Fix multi-line support.
-      #MockFile('dir/java/src/mult.cc', [
-      #  'barVeryVeryLongLongBaaaaaarSoThatTheLineLimitIsAlmostReached =',
-      #  '    std::unique_ptr<T>(foo);'
-      #]),
+      MockFile('dir/java/src/mult.cc', [
+        'return',
+        '    std::unique_ptr<T>(barVeryVeryLongFooSoThatItWouldNotFitAbove);'
+      ]),
+      MockFile('dir/java/src/mult2.cc', [
+        'barVeryVeryLongLongBaaaaaarSoThatTheLineLimitIsAlmostReached =',
+        '    std::unique_ptr<T>(foo);'
+      ]),
+      MockFile('dir/java/src/mult3.cc', [
+        'bar = std::unique_ptr<T>(',
+        '    fooVeryVeryVeryLongStillGoingWellThisWillTakeAWhileFinallyThere);'
+      ]),
     ]
 
     results = PRESUBMIT._CheckUniquePtr(mock_input_api, MockOutputApi())
     # TODO(crbug.com/827961) Make the check return just one result, listing all
     # affected files in it.
-    self.assertEqual(4, len(results))
+    self.assertEqual(7, len(results))
     self.assertTrue('foo.cc' in results[0].message)
     self.assertTrue('bar.mm' in results[1].message)
     self.assertTrue('baz.cc' in results[2].message)
     self.assertTrue('baz-p.cc' in results[3].message)
+    self.assertTrue('mult.cc' in results[4].message)
+    self.assertTrue('mult2.cc' in results[5].message)
+    self.assertTrue('mult3.cc' in results[6].message)
 
   def testFalsePositives(self):
     mock_input_api = MockInputApi()