adbd: improve coverage by compiling less code.

Test: ./coverage/gen_coverage.sh && ./coverage/report.sh
Change-Id: I26f823e2587435b7ec2c6ca05955adef5cfc23a0

adb/Android.bp

@@ -165,7 +165,6 @@ libadb_srcs = [
     "adb_unique_fd.cpp",
     "adb_utils.cpp",
     "fdevent/fdevent.cpp",
-    "fdevent/fdevent_poll.cpp",
     "services.cpp",
     "sockets.cpp",
     "socket_spec.cpp",
@@ -176,6 +175,17 @@ libadb_srcs = [
     "types.cpp",
 ]
 
+libadb_darwin_srcs = [
+    "fdevent/fdevent_poll.cpp",
+]
+
+libadb_windows_srcs = [
+    "fdevent/fdevent_poll.cpp",
+    "sysdeps_win32.cpp",
+    "sysdeps/win32/errno.cpp",
+    "sysdeps/win32/stat.cpp",
+]
+
 libadb_posix_srcs = [
     "sysdeps_unix.cpp",
     "sysdeps/posix/network.cpp",
@@ -219,7 +229,7 @@ cc_library_host_static {
             srcs: ["client/usb_linux.cpp"] + libadb_linux_srcs,
         },
         darwin: {
-            srcs: ["client/usb_osx.cpp"],
+            srcs: ["client/usb_osx.cpp"] + libadb_darwin_srcs,
         },
         not_windows: {
             srcs: libadb_posix_srcs,
@@ -228,10 +238,7 @@ cc_library_host_static {
             enabled: true,
             srcs: [
                 "client/usb_windows.cpp",
-                "sysdeps_win32.cpp",
-                "sysdeps/win32/errno.cpp",
-                "sysdeps/win32/stat.cpp",
-            ],
+            ] + libadb_windows_srcs,
             shared_libs: ["AdbWinApi"],
         },
     },

adb/adb_trace.cpp

@@ -89,18 +89,13 @@ void start_device_log(void) {
 
 int adb_trace_mask;
 
-std::string get_trace_setting_from_env() {
+std::string get_trace_setting() {
+#if ADB_HOST
     const char* setting = getenv("ADB_TRACE");
     if (setting == nullptr) {
         setting = "";
     }
-
-    return std::string(setting);
-}
-
-std::string get_trace_setting() {
-#if ADB_HOST
-    return get_trace_setting_from_env();
+    return setting;
 #else
     return android::base::GetProperty("persist.adb.trace_mask", "");
 #endif

adb/fdevent/fdevent.cpp

@@ -27,7 +27,10 @@
 #include "adb_utils.h"
 #include "fdevent.h"
 #include "fdevent_epoll.h"
+
+#if !defined(__linux__)
 #include "fdevent_poll.h"
+#endif
 
 using namespace std::chrono_literals;
 using std::chrono::duration_cast;