Add entry to known_crashes.txt for 83657.

(base::internal::lockimpl::lock___extensioncontentsettingsstore::geteffectivecontentsetting___content_settings::extensionprovider::getcontentsetting)

BUG=83657
TEST=reliability bots

Review URL: http://codereview.chromium.org/7064007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@86347 0039d316-1c4b-4281-b951-d872f2087c98

chrome/test/data/reliability/known_crashes.txt

@@ -171,3 +171,6 @@ PREFIX: webcore::implicitanimation::~implicitanimation___webcore::implicitanimat
 
 # 21054
 REGEX : ^deletetask.*::run___messageloop::runtask___messageloop::dowork
+
+# 83657
+PREFIX: base::internal::lockimpl::lock___extensioncontentsettingsstore::geteffectivecontentsetting___content_settings::extensionprovider::getcontentsetting