Switch third_party/gflags to use updated GitHub repo.

DEPS

 # This file contains dependencies for WebRTC that are not shared with Chromium.
 # If you wish to add a dependency that is present in Chromium's src/DEPS or a
 # directory from the Chromium checkout, you should add it to setup_links.py
 # instead.
 
 vars = {
   'extra_gyp_flag': '-Dextra_gyp_flag=0',
   'chromium_git': 'https://chromium.googlesource.com',
   'chromium_revision': '3a90ecfeb74acfc47de7df8b531ef30aa743f296',
 }
 
-# NOTE: Prefer revision numbers to tags for svn deps. Use http rather than
-# https; the latter can cause problems for users behind proxies.
+# NOTE: Use http rather than https; the latter can cause problems for users
+# behind proxies.
 deps = {
-  # When rolling gflags, also update
-  # https://chromium.googlesource.com/chromium/deps/webrtc/webrtc.DEPS
   'src/third_party/gflags/src':
-    Var('chromium_git') + '/external/gflags/src@e7390f9185c75f8d902c05ed7d20bb94eb914d0c', # from svn revision 82
+    Var('chromium_git') + '/external/github.com/gflags/gflags@03bebcb065c83beff83d50ae025a55a4bf94dfca',
 }
 
 deps_os = {
   'win': {
     'src/third_party/winsdk_samples/src':
       Var('chromium_git') + '/external/webrtc/deps/third_party/winsdk_samples_v71@e71b549167a665d7424d6f1dadfbff4b4aad1589',
   },
 }
 
 # Define rules for which include paths are allowed in our source.
@@ skipping 77 matching lines @@
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     'name': 'gyp',
     'pattern': '.',
     'action': ['python', 'src/webrtc/build/gyp_webrtc',
                Var('extra_gyp_flag')],
   },
 ]