Report style errors in lines near changed lines.

Change-Id: I10f190b377295e5f6bab1e2672f566ccf75912d6

lint/lint.go

diff --git a/lint/lint.go b/lint/lint.go
index 218c378..485c267 100644
--- a/lint/lint.go
+++ b/lint/lint.go
@@ -146,8 +146,11 @@
 
 func (l *linter) addCheckStyleComments(file checkstyle.File, blameable map[int]bool) {
 	for _, err := range file.Errors {
-		if blameable[err.Line] {
-			l.comment(file.Name, err.Line, err.Severity, err.Message)
+		for i := 0; i < 3; i++ {
+			if blameable[err.Line-i] || blameable[err.Line+i] {
+				l.comment(file.Name, err.Line, err.Severity, err.Message)
+				break
+			}
 		}
 	}
 }

lint/lint_test.go

diff --git a/lint/lint_test.go b/lint/lint_test.go
index ce25a69..16a050e 100644
--- a/lint/lint_test.go
+++ b/lint/lint_test.go
@@ -64,6 +64,22 @@
 			},
 			blameable: []int{1, 2, 3},
 		},
+		{
+			errors: []checkstyle.Error{
+				checkstyle.Error{
+					Line:     5,
+					Severity: "warning",
+					Message:  "Warning near a changed line",
+				},
+			},
+			blameable: []int{1, 2, 3},
+			comments: []gerrit.Comment{
+				gerrit.Comment{
+					Line:    5,
+					Message: "[warning] Warning near a changed line",
+				},
+			},
+		},
 	}
 
 	for _, test := range tests {