Reland "[ios] Add --landmines-path to build/landmines.py script"

This is a reland of aafd725

Original change's description:
> [ios] Add --landmines-path to build/landmines.py script
> 
> Chrome on iOS has some internal landmines and uses a forked version
> of build/landmines.py for that to allow using a separate landmines
> file.
> 
> Add a --landmines-path parameter to build/landmines.py script in
> order to remove the forked version and instead use the shared one.
> 
> Bug: 1033067
> Change-Id: Iac668c5877ae181442078cda7ce8e727f91104b4
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2283582
> Reviewed-by: Dirk Pranke <dpranke@google.com>
> Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#786218}

Bug: 1033067
Change-Id: Ice49ba16caf21045e0b513fb4b55cf198d3f0d36
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2287477
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Dirk Pranke <dpranke@google.com>
Cr-Commit-Position: refs/heads/master@{#786352}

DEPS

@@ -4090,6 +4090,23 @@ hooks = [
         'src/build/landmines.py',
     ],
   },
+  {
+    # This clobbers when necessary (based on get_landmines.py). It must be the
+    # first hook so that other things that get/generate into the output
+    # directory will not subsequently be clobbered. This script is only run
+    # for iOS build with src_internal.
+    'name': 'landmines_ios_internal',
+    'pattern': '.',
+    'condition': 'checkout_ios and checkout_src_internal',
+    'action': [
+        'python',
+        'src/build/landmines.py',
+        '--landmine-scripts',
+        'src/ios_internal/build/get_landmines.py',
+        '--landmines-path',
+        'src/ios_internal/.landmines',
+    ],
+  },
   {
     # Ensure that the DEPS'd "depot_tools" has its self-update capability
     # disabled.

build/landmines.py

@@ -55,10 +55,9 @@ def get_build_dir(src_dir):
   return os.path.abspath(os.path.join(src_dir, output_dir))
 
 
-def clobber_if_necessary(new_landmines, src_dir):
+def clobber_if_necessary(new_landmines, src_dir, landmines_path):
   """Does the work of setting, planting, and triggering landmines."""
   out_dir = get_build_dir(src_dir)
-  landmines_path = os.path.normpath(os.path.join(src_dir, '.landmines'))
   try:
     os.makedirs(out_dir)
   except OSError as e:
@@ -95,6 +94,10 @@ def process_options():
   parser.add_option('-d', '--src-dir',
       help='Path of the source root dir. Overrides the default location of the '
            'source root dir when calculating the build directory.')
+  parser.add_option(
+      '-l',
+      '--landmines-path',
+      help='Path to the landmines file to use (defaults to .landmines)')
   parser.add_option('-v', '--verbose', action='store_true',
       default=('LANDMINES_VERBOSE' in os.environ),
       help=('Emit some extra debugging information (default off). This option '
@@ -137,7 +140,12 @@ def main():
                             universal_newlines=True)
     output, _ = proc.communicate()
     landmines.extend([('%s\n' % l.strip()) for l in output.splitlines()])
-  clobber_if_necessary(landmines, options.src_dir)
+  if options.landmines_path:
+    landmines_path = options.landmines_path
+  else:
+    landmines_path = os.path.join(options.src_dir, '.landmines')
+  clobber_if_necessary(landmines, options.src_dir,
+                       os.path.normpath(landmines_path))
 
   return 0