Test srcset parsing for space in url

A false bug report led me to the realization that srcset's unit testing didn't include URLs with encoded spaces in them.
Added such a test here.

BUG=422914

Review URL: https://codereview.chromium.org/643703005

git-svn-id: svn://svn.chromium.org/blink/trunk@183858 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/html/parser/HTMLSrcsetParserTest.cpp

@@ -103,6 +103,7 @@ TEST(HTMLSrcsetParserTest, Basic)
         {1.0, -1, "", "data:,a +1x", "", 1.0, -1},
         {1.0, -1, "", "data:,a   +1x", "", 1.0, -1},
         {1.0, -1, "", "data:,a 1.0x", "data:,a", 1.0, -1},
+        {1.0, -1, "", "1%20and%202.gif 1x", "1%20and%202.gif", 1.0, -1},
         {0, 0, 0, 0, 0, 0} // Do not remove the terminator line.
     };