Add a stale .pyc cleanup step before running gyp

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 729 matching lines @@
               ],
   },
   {
     # Pull sanitizer-instrumented third-party libraries if requested via
     # GYP_DEFINES.
     'name': 'instrumented_libraries',
     'pattern': '\\.sha1',
     'action': ['python', 'src/third_party/instrumented_libraries/scripts/download_binaries.py'],
   },
   {
+    # Ensure that while generating dependencies lists in .gyp files we don't
+    # accidentally reference any .pyc files whose corresponding .py files have
+    # already been deleted.
+    # We should actually try to avoid generating .pyc files, crbug.com/500078.
+    'name': 'remove_stale_pyc_files',
+    'pattern': '.',
+    'action': [
+        'python',
+        'src/tools/remove_stale_pyc_files.py',
+        'src/android_webview/tools',
+        'src/gpu/gles2_conform_support',
+        'src/ppapi',
+        'src/printing',
+        'src/third_party/closure_compiler/build',
+        'src/tools',
+    ],
+  },
+  {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     'name': 'gyp',
     'pattern': '.',
     'action': ['python', 'src/build/gyp_chromium'],
   },
   {
     # Verify committers' ~/.netc, gclient and git are properly configured for
     # write access to the git repo. To be removed sometime after Chrome to git
     # migration completes (let's say Sep 1 2014).
     'name': 'check_git_config',
     'pattern': '.',
     'action': [
         'python',
         'src/tools/check_git_config.py',
         '--running-as-hook',
     ],
   },
-  {
-    # Ensure that we don't accidentally reference any .pyc files whose
-    # corresponding .py files have already been deleted.
-    'name': 'remove_stale_pyc_files',
-    'pattern': 'src/tools/.*\\.py',
-    'action': [
-        'python',
-        'src/tools/remove_stale_pyc_files.py',
-        'src/tools',
-    ],
-  },
 ]