Add function for getting supported H264 level from max resolution and fps

webrtc/common_video/h264/profile_level_id_unittest.cc

Index: webrtc/common_video/h264/profile_level_id_unittest.cc
diff --git a/webrtc/common_video/h264/profile_level_id_unittest.cc b/webrtc/common_video/h264/profile_level_id_unittest.cc
index 8237b20c2bb7da6fb31852430cce9d658f2282a8..f6b420b661ca4da757899b3bb844078eef6f6074 100644
--- a/webrtc/common_video/h264/profile_level_id_unittest.cc
+++ b/webrtc/common_video/h264/profile_level_id_unittest.cc
@@ -70,6 +70,12 @@ TEST(H264ProfileLevelId, TestParsingConstrainedHigh) {
   EXPECT_EQ(kProfileConstrainedHigh, ParseProfileLevelId("640c1f")->profile);
 }
 
+TEST(H264ProfileLevelId, TestSupportedLevel) {
+  EXPECT_EQ(kLevel2_1, SupportedLevel(640 * 480, 25));
+  EXPECT_EQ(kLevel3_1, SupportedLevel(1280 * 720, 30));
+  EXPECT_EQ(kLevel4_2, SupportedLevel(1920 * 1280, 60));
+}
+
 TEST(H264ProfileLevelId, TestToString) {
   EXPECT_EQ("42e01f", ProfileLevelIdToString(ProfileLevelId(
                           kProfileConstrainedBaseline, kLevel3_1)));