Proguard conditional keeps for layouts

Added flag for aapt2 link to generate proguard conditional keep rules.

Bug: 682786
Change-Id: I11e7afd5b540bcc6bc0f4bf54a8bd20c750fb0a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1723796
Commit-Queue: Harsh Patel <harshpa@google.com>
Reviewed-by: Sam Maier <smaier@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#684463}

build/android/gyp/compile_resources.py

@@ -723,6 +723,7 @@ def _PackageApk(options, build):
       options.min_sdk_version,
       '--target-sdk-version',
       options.target_sdk_version,
+      '--proguard-conditional-keep-rules',
   ]
 
   for j in options.include_resources:

chrome/android/java/monochrome_public_bundle.proguard_flags.expected

@@ -359,6 +359,18 @@
   public <init>();
 }
 
+################################################################################
+# ../../third_party/android_deps/appcompat_extra.flags
+################################################################################
+# These flags are used as a temporary fix for an aapt2 bug.
+# Remove this file and update BuildConfigGenerator.groovy to not use this file
+# for proguard.
+#
+# Link for Googlers: go/aapt-conditional-keep-bug.
+
+-if class **.R$styleable { int AlertDialog_android_layout; }
+-keep class **.R$layout { int abc_alert_dialog_material; }
+
 ################################################################################
 # ../../third_party/gvr-android-sdk/proguard-gvr-chromium.txt
 ################################################################################

third_party/android_deps/BUILD.gn

@@ -164,6 +164,9 @@ android_aar_prebuilt("com_android_support_appcompat_v7_java") {
     ":com_android_support_support_fragment_java",
     ":com_android_support_support_vector_drawable_java",
   ]
+  if (!is_java_debug) {
+    proguard_configs = [ "appcompat_extra.flags" ]
+  }
 }
 
 # This is generated, do not edit. Update BuildConfigGenerator.groovy instead.

third_party/android_deps/README.chromium

@@ -17,6 +17,7 @@ Everything directly here is chromium code, and third_party code lives under
 ```
 third_party/android_deps
 ├── .gitignore (hand written)
+├── appcompat_extra.flags (hand written)
 ├── Android_SDK_License-December_9_2016.txt ([1])
 ├── additional_license_paths.json (generated)
 ├── BUILD.gn (partly generated)

third_party/android_deps/appcompat_extra.flags

+# These flags are used as a temporary fix for an aapt2 bug.
+# Remove this file and update BuildConfigGenerator.groovy to not use this file
+# for proguard.
+#
+# Link for Googlers: go/aapt-conditional-keep-bug.
+
+-if class **.R$styleable { int AlertDialog_android_layout; }
+-keep class **.R$layout { int abc_alert_dialog_material; }
\ No newline at end of file

tools/android/roll/android_deps/buildSrc/src/main/groovy/BuildConfigGenerator.groovy

@@ -243,6 +243,11 @@ class BuildConfigGenerator extends DefaultTask {
                 sb.append('  # https://crbug.com/887942#c1\n')
                 sb.append('  ignore_proguard_configs = true\n')
                 break
+            case 'com_android_support_appcompat_v7':
+                sb.append('  if (!is_java_debug) {\n')
+                sb.append('    proguard_configs = ["appcompat_extra.flags"]\n')
+                sb.append('  }\n')
+                break
             case 'com_android_support_support_compat':
             case 'com_android_support_support_media_compat':
                 // Target has AIDL, but we don't support it yet: http://crbug.com/644439