Move emulator tracing into its own file.

adb.c is far too monolithic.

Change-Id: I4a9ee97927e4a96a38ea5859d84efac86bfdfc35
diff --git a/adb/Android.mk b/adb/Android.mk
index ba20bbe..83d168b 100644
--- a/adb/Android.mk
+++ b/adb/Android.mk
@@ -23,7 +23,12 @@
 include $(CLEAR_VARS)
 LOCAL_MODULE := libadbd
 LOCAL_CFLAGS := $(LIBADB_CFLAGS) -DADB_HOST=0
-LOCAL_SRC_FILES := $(LIBADB_SRC_FILES) $(LIBADB_LINUX_SRC_FILES) usb_linux_client.c
+LOCAL_SRC_FILES := \
+    $(LIBADB_SRC_FILES) \
+    $(LIBADB_LINUX_SRC_FILES) \
+    qemu_tracing.c \
+    usb_linux_client.c \
+
 include $(BUILD_STATIC_LIBRARY)
 
 include $(CLEAR_VARS)