Suppress the AlertDialog presubmit warning when not useful

tools/android/checkstyle/suppressions.xml

Index: tools/android/checkstyle/suppressions.xml
diff --git a/tools/android/checkstyle/suppressions.xml b/tools/android/checkstyle/suppressions.xml
index 57ba3cede9b9a7da6ed6e6413e9f2a09e457c375..9ae1852ec53226a43a00429b1f1529f14c959184 100644
--- a/tools/android/checkstyle/suppressions.xml
+++ b/tools/android/checkstyle/suppressions.xml
@@ -3,6 +3,5 @@
 
 <suppressions>
   <suppress id="SharedPreferencesCheck" files="ContextUtils.java"/>
-  <!-- TODO(crbug.com/635567): Fix this properly. -->
-  <suppress id="AlertDialogCheck" files="MultiFieldTimePickerDialog.java"/>
+  <suppress id="AlertDialogCheck" files="src/content/"/>

[Ted C, 2016/10/05 16:10:12]

really, we want to suppress this for every directory but chrome...don't know if
that is possible though.

[wychen, 2016/10/06 23:12:28]

What about blimp/ and remoting/? They already have
android.support.v7.app.AlertDialog usage. I think it makes sense to add these to
our whitelist as well.

This suppression list only works by using a regex to match file names, so the
best we can do here is to enumerate all the directory names under src/ except
for the whitelisted ones. It's not ideal, but since it's pretty rare to add
top-level directories under src/, we don't have to worry about updating this
often.

 </suppressions>