Fix Chromium clang plugin warnings

This adds a new file, webrtc/modules/audio_coding/neteq/tools/packet_source.cc, so that I'll have somewhere to put the new non-inlined methods.

NOTRY=true
BUG=webrtc:163

Review-Url: https://codereview.webrtc.org/2290593002
Cr-Commit-Position: refs/heads/master@{#13956}
diff --git a/webrtc/modules/audio_coding/BUILD.gn b/webrtc/modules/audio_coding/BUILD.gn
index 0313b2b..2925e08 100644
--- a/webrtc/modules/audio_coding/BUILD.gn
+++ b/webrtc/modules/audio_coding/BUILD.gn
@@ -898,11 +898,6 @@
     configs += [ "../..:common_config" ]
     public_configs = [ "../..:common_inherited_config" ]
 
-    if (is_clang) {
-      # Suppress warnings from the Chromium Clang plugins (bugs.webrtc.org/163).
-      configs -= [ "//build/config/clang:find_bad_constructs" ]
-    }
-
     defines = audio_coding_defines
 
     deps = audio_coding_deps + [
@@ -1209,6 +1204,7 @@
       "neteq/tools/output_wav_file.h",
       "neteq/tools/packet.cc",
       "neteq/tools/packet.h",
+      "neteq/tools/packet_source.cc",
       "neteq/tools/packet_source.h",
       "neteq/tools/resample_input_audio_file.cc",
       "neteq/tools/resample_input_audio_file.h",