diff --git a/runtime/bin/bin.gypi b/runtime/bin/bin.gypi
index 3637a4f40ef..dfe9a74698b 100644
--- a/runtime/bin/bin.gypi
+++ b/runtime/bin/bin.gypi
@@ -13,6 +13,7 @@
     'snapshot_in_cc_file': 'snapshot_in.cc',
     'vm_isolate_snapshot_bin_file': '<(gen_source_dir)/vm_isolate_snapshot_gen.bin',
     'isolate_snapshot_bin_file': '<(gen_source_dir)/isolate_snapshot_gen.bin',
+    'gen_snapshot_stamp_file': '<(gen_source_dir)/gen_snapshot.stamp',
     'resources_cc_file': '<(gen_source_dir)/resources_gen.cc',
     'bootstrap_resources_cc_file':
         '<(gen_source_dir)/bootstrap_resources_gen.cc',
@@ -420,8 +421,7 @@
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)gen_snapshot<(EXECUTABLE_SUFFIX)',
           ],
           'outputs': [
-            '<(vm_isolate_snapshot_bin_file)',
-            '<(isolate_snapshot_bin_file)',
+            '<(gen_snapshot_stamp_file)',
           ],
           'action': [
             'python',
@@ -430,7 +430,8 @@
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)gen_snapshot<(EXECUTABLE_SUFFIX)',
             '--vm_output_bin', '<(vm_isolate_snapshot_bin_file)',
             '--output_bin', '<(isolate_snapshot_bin_file)',
-            '--target_os', '<(OS)'
+            '--target_os', '<(OS)',
+            '--timestamp_file', '<(gen_snapshot_stamp_file)',
           ],
           'message': 'Generating ''<(vm_isolate_snapshot_bin_file)'' ''<(isolate_snapshot_bin_file)'' files.'
         },
@@ -449,9 +450,8 @@
           'action_name': 'generate_snapshot_file',
           'inputs': [
             '../tools/create_snapshot_file.py',
+            '<(gen_snapshot_stamp_file)',
             '<(snapshot_in_cc_file)',
-            '<(vm_isolate_snapshot_bin_file)',
-            '<(isolate_snapshot_bin_file)',
           ],
           'outputs': [
             '<(snapshot_cc_file)',
diff --git a/runtime/tools/create_snapshot_bin.py b/runtime/tools/create_snapshot_bin.py
index 19c29434b77..b91de38e863 100755
--- a/runtime/tools/create_snapshot_bin.py
+++ b/runtime/tools/create_snapshot_bin.py
@@ -52,6 +52,10 @@ def BuildOptions():
   result.add_option("--abi",
       action="store", type="string",
       help="Desired ABI for android target OS. armeabi-v7a or x86")
+  result.add_option("--timestamp_file",
+      action="store", type="string",
+      help="Path to timestamp file that will be written",
+      default="")
   return result
 
 
@@ -71,6 +75,14 @@ def ProcessOptions(options):
   return True
 
 
+def CreateTimestampFile(options):
+  if options.timestamp_file != '':
+    dir_name = os.path.dirname(options.timestamp_file)
+    if not os.path.exists(dir_name):
+      os.mkdir(dir_name)
+    open(options.timestamp_file, 'w').close()
+
+
 def Main():
   # Parse options.
   parser = BuildOptions()
@@ -113,6 +125,9 @@ def Main():
   except Exception as e:
     return -1
 
+  # Success, update timestamp file.
+  CreateTimestampFile(options)
+
   return 0
 
 
diff --git a/tools/observatory_tool.py b/tools/observatory_tool.py
index fab21834b42..66261438f1c 100755
--- a/tools/observatory_tool.py
+++ b/tools/observatory_tool.py
@@ -96,6 +96,8 @@ def PubBuild(dart_executable, pub_executable, pkg_root, silent, output_dir):
 def Deploy(input_dir, output_dir):
   shutil.rmtree(output_dir)
   shutil.copytree(input_dir, output_dir, ignore=IGNORE_PATTERNS)
+  index_file = os.path.join(output_dir, 'web', 'index.html')
+  os.utime(index_file, None)
   return 0
 
 def RewritePubSpec(input_path, output_path, search, replace):