Android: Adding min_api for r8 dexing.

Bug: 872904
Change-Id: I44e020b7d7d121650f4c292b71b4d2dbc45fa9f3
Reviewed-on: https://chromium-review.googlesource.com/c/1277765Reviewed-by: agrieve <agrieve@chromium.org>
Commit-Queue: Sam Maier <smaier@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599198}

build/android/gyp/proguard.py

@@ -66,6 +66,8 @@ def _ParseOptions(args):
   parser.add_option('--main-dex-rules-path', action='append',
                     help='Paths to main dex rules for multidex'
                          '- only works with R8.')
+  parser.add_option('--min-api', default='',
+                    help='Minimum Android API level compatibility.')
   parser.add_option('--verbose', '-v', action='store_true',
                     help='Print all proguard output')
 
@@ -73,6 +75,8 @@ def _ParseOptions(args):
 
   assert not options.main_dex_rules_path or options.r8_path, \
       "R8 must be enabled to pass main dex rules."
+  assert not options.min_api or options.r8_path, \
+      "R8 must be enabled to pass min api."
 
   classpath = []
   for arg in options.classpath:
@@ -132,6 +136,9 @@ def _CreateR8Command(options, map_output_path, output_dir):
   for config_file in options.proguard_configs:
     cmd += ['--pg-conf', config_file]
 
+  if options.min_api:
+    cmd += ['--min-api', options.min_api]
+
   if options.main_dex_rules_path:
     for main_dex_rule in options.main_dex_rules_path:
       cmd += ['--main-dex-rules', main_dex_rule]

build/config/android/internal_rules.gni

@@ -1131,6 +1131,13 @@ if (enable_java_templates) {
           args += invoker.proguard_args
         }
 
+        if (_proguarding_with_r8 && defined(invoker.min_sdk_version)) {
+          args += [
+            "--min-api",
+            "${invoker.min_sdk_version}",
+          ]
+        }
+
         output_path = _proguard_output_path
       }
     }