Fix linker error when building without internal audio device.

Bug: webrtc:8678
Change-Id: I30f0d1aa7bec6931edb9e5ba00a6813dea1536ff
Reviewed-on: https://webrtc-review.googlesource.com/35480
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Commit-Queue: Henrik Andreassson <henrika@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21408}

modules/audio_device/BUILD.gn

@@ -364,6 +364,9 @@ if (rtc_include_tests) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
+    if (!rtc_include_internal_audio_device) {
+      defines = [ "WEBRTC_DUMMY_AUDIO_BUILD" ]
+    }
   }
 }
 

modules/audio_device/audio_device_unittest.cc

@@ -455,7 +455,8 @@ class MockAudioTransport : public test::MockAudioTransport {
 class AudioDeviceTest : public ::testing::Test {
  protected:
   AudioDeviceTest() : event_(false, false) {
-#if !defined(ADDRESS_SANITIZER) && !defined(MEMORY_SANITIZER)
+#if !defined(ADDRESS_SANITIZER) && !defined(MEMORY_SANITIZER) && \
+    !defined(WEBRTC_DUMMY_AUDIO_BUILD)
     rtc::LogMessage::LogToDebug(rtc::LS_INFO);
     // Add extra logging fields here if needed for debugging.
     // rtc::LogMessage::LogTimestamps();