Get rid of LASTCHANGE.blink

Now that blink lives in the src repo, there's no need to generate a
separate LASTCHANGE file for it.

The LASTCHANGE line makes it into the user agent. LASTCHANGE.blink
used --git-hash-only to only have the git hash in there.  Remove
that now-unused flag and use version.py's -e flag to get the same
effect for webkit_version.h

Reverts parts of https://chromiumcodereview.appspot.com/14973005/
No intended behavior change.

BUG=none

Review-Url: https://codereview.chromium.org/1982423002
Cr-Commit-Position: refs/heads/master@{#465739}

DEPS

@@ -837,15 +837,6 @@ hooks = [
     'action': ['python', 'src/build/util/lastchange.py',
                '-o', 'src/build/util/LASTCHANGE'],
   },
-  {
-    # Update LASTCHANGE.blink.
-    'name': 'lastchange_blink',
-    'pattern': '.',
-    'action': ['python', 'src/build/util/lastchange.py',
-               '--git-hash-only',
-               '-s', 'src/third_party/WebKit',
-               '-o', 'src/build/util/LASTCHANGE.blink'],
-  },
   {
     # Update skia_commit_hash.h.
     'name': 'lastchange_skia',

build/util/BUILD.gn

@@ -5,7 +5,7 @@
 action("webkit_version") {
   script = "version.py"
 
-  lastchange_file = "LASTCHANGE.blink"
+  lastchange_file = "LASTCHANGE"
 
   template_file = "webkit_version.h.in"
   inputs = [
@@ -19,6 +19,10 @@ action("webkit_version") {
   ]
 
   args = [
+    # LASTCHANGE contains "<build hash>-<ref>".  The user agent only wants the
+    # "<build hash>" bit, so chop off everything after it.
+    "-e",
+    "LASTCHANGE=LASTCHANGE[:LASTCHANGE.find('-')]",
     "-f",
     rebase_path(lastchange_file, root_build_dir),
     rebase_path(template_file, root_build_dir),

build/util/lastchange.py

@@ -48,7 +48,7 @@ def RunGitCommand(directory, command):
     return None
 
 
-def FetchGitRevision(directory, hash_only):
+def FetchGitRevision(directory):
   """
   Fetch the Git hash for a given directory.
 
@@ -59,8 +59,6 @@ def FetchGitRevision(directory, hash_only):
   """
   hsh = ''
   git_args = ['log', '-1', '--format=%H']
-  if hash_only:
-    git_args.append('--grep=^Cr-Commit-Position:')
   proc = RunGitCommand(directory, git_args)
   if proc:
     output = proc.communicate()[0].strip()
@@ -77,14 +75,11 @@ def FetchGitRevision(directory, hash_only):
         if line.startswith('Cr-Commit-Position:'):
           pos = line.rsplit()[-1].strip()
           break
-  if hash_only or not pos:
-    return VersionInfo('git', hsh)
   return VersionInfo('git', '%s-%s' % (hsh, pos))
 
 
 def FetchVersionInfo(directory=None,
-                     directory_regex_prior_to_src_url='chrome|blink|svn',
-                     hash_only=False):
+                     directory_regex_prior_to_src_url='chrome|svn'):
   """
   Returns the last change (in the form of a branch, revision tuple),
   from some appropriate revision control system.
@@ -92,7 +87,7 @@ def FetchVersionInfo(directory=None,
   svn_url_regex = re.compile(
       r'.*/(' + directory_regex_prior_to_src_url + r')(/.*)')
 
-  version_info = FetchGitRevision(directory, hash_only)
+  version_info = FetchGitRevision(directory)
   if not version_info:
     version_info = VersionInfo(None, None)
   return version_info
@@ -173,9 +168,6 @@ def main(argv=None):
                     "file-output-related options.")
   parser.add_option("-s", "--source-dir", metavar="DIR",
                     help="Use repository in the given directory.")
-  parser.add_option("--git-hash-only", action="store_true",
-                    help="In a Git repo with commit positions, report only " +
-                    "the hash of the latest commit with a position.")
   opts, args = parser.parse_args(argv[1:])
 
   out_file = opts.output
@@ -194,8 +186,7 @@ def main(argv=None):
   else:
     src_dir = os.path.dirname(os.path.abspath(__file__))
 
-  version_info = FetchVersionInfo(directory=src_dir,
-                                  hash_only=opts.git_hash_only)
+  version_info = FetchVersionInfo(directory=src_dir)
 
   if version_info.revision == None:
     version_info.revision = '0'