Changed AECM to be built using C++

webrtc/modules/audio_processing/BUILD.gn

Index: webrtc/modules/audio_processing/BUILD.gn
diff --git a/webrtc/modules/audio_processing/BUILD.gn b/webrtc/modules/audio_processing/BUILD.gn
index 22c904d52f2d2c350de875abb8a1a41a0e83e687..1060ec8871ff2ca03701a99749df7eca0c43cdb0 100644
--- a/webrtc/modules/audio_processing/BUILD.gn
+++ b/webrtc/modules/audio_processing/BUILD.gn
@@ -32,9 +32,9 @@ source_set("audio_processing") {
     "aec/echo_cancellation.cc",
     "aec/echo_cancellation.h",
     "aec/echo_cancellation_internal.h",
-    "aecm/aecm_core.c",
+    "aecm/aecm_core.cc",
     "aecm/aecm_core.h",
-    "aecm/echo_control_mobile.c",
+    "aecm/echo_control_mobile.cc",
     "aecm/echo_control_mobile.h",
     "agc/agc.cc",
     "agc/agc.h",
@@ -196,7 +196,7 @@ source_set("audio_processing") {
   }
 
   if (current_cpu == "mipsel") {
-    sources += [ "aecm/aecm_core_mips.c" ]
+    sources += [ "aecm/aecm_core_mips.cc" ]
     if (mips_float_abi == "hard") {
       sources += [
         "aec/aec_core_mips.cc",
@@ -204,7 +204,7 @@ source_set("audio_processing") {
       ]
     }
   } else {
-    sources += [ "aecm/aecm_core_c.c" ]
+    sources += [ "aecm/aecm_core_c.cc" ]
   }
 
   if (is_win) {
@@ -258,7 +258,7 @@ if (rtc_build_with_neon) {
     sources = [
       "aec/aec_core_neon.cc",
       "aec/aec_rdft_neon.c",
-      "aecm/aecm_core_neon.c",
+      "aecm/aecm_core_neon.cc",
       "ns/nsx_core_neon.c",
     ]