Add input content checking to some build scripts

build/android/gyp/push_libraries.py

Index: build/android/gyp/push_libraries.py
diff --git a/build/android/gyp/push_libraries.py b/build/android/gyp/push_libraries.py
index 9c7366e5e7b23d6f34e78b475dc3f71d34e6fc42..9a32760d55704de96096975d39cc113060aebde5 100755
--- a/build/android/gyp/push_libraries.py
+++ b/build/android/gyp/push_libraries.py
@@ -13,6 +13,8 @@ import optparse
 import os
 import sys
 
+from util import md5_check
+
 BUILD_ANDROID_DIR = os.path.join(os.path.dirname(__file__), '..')
 sys.path.append(BUILD_ANDROID_DIR)
 
@@ -24,11 +26,19 @@ def DoPush(options):
   libraries = build_utils.ReadJson(options.libraries_json)
 
   adb = android_commands.AndroidCommands()
-  adb.RunShellCommand('mkdir ' + options.device_dir)
+  needs_directory = True
   for lib in libraries:
     device_path = os.path.join(options.device_dir, lib)
     host_path = os.path.join(options.libraries_dir, lib)
-    adb.PushIfNeeded(host_path, device_path)
+
+    md5_stamp = '%s.%s.md5' % (host_path, adb.Adb().GetSerialNumber())
+    md5_checker = md5_check.Md5Checker(stamp=md5_stamp, inputs=[host_path])
+    if md5_checker.IsStale():
+      if needs_directory:
+        adb.RunShellCommand('mkdir ' + options.device_dir)
+        needs_directory = False
+      adb.PushIfNeeded(host_path, device_path)
+    md5_checker.Write()
 
 
 def main(argv):