Add proguard rules for BaseGmsClient to keep Api$Client methods

BaseGmsClient provides the methods required for its subclass GmsClient
to correctly implement Api$Client. Those methods appear to be removed by
R8, leading to an AbstractMethodError calling dump.

Mark all the methods that are currently kept in the interface as -keep
in proguard configs.

Bug: 1002847
Test: Decompile to verify methods not removed.
Test: Manually verify that crbug/1002847 no longer reproduces
Change-Id: I22b0610bdb49df40645517c0d428a587c3d1563f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1805655
Commit-Queue: Tobias Sargeant <tobiasjs@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Reviewed-by: Sam Maier <smaier@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696865}

android_webview/apk/java/proguard.flags

@@ -63,3 +63,14 @@
 # Trichrome builds don't include a native library list in the main APK; it's
 # picked up from the library APK at runtime.
 -dontwarn org.chromium.base.library_loader.NativeLibraries
+
+# Workaround for crbug/1002847. Methods of BaseGmsClient are incorrectly
+# removed even though they are required for the derived class GmsClient
+# to correctly implement Api$Client.
+# TODO: remove once crbug/1002847 resolved.
+-keep public class com.google.android.gms.common.internal.BaseGmsClient {
+  public void disconnect();
+  public void dump(java.lang.String,java.io.FileDescriptor,java.io.PrintWriter,java.lang.String[]);
+  public int getMinApkVersion();
+  public boolean requiresSignIn();
+}

chrome/android/java/monochrome_public_bundle.proguard_flags.expected

@@ -67,6 +67,17 @@
 # picked up from the library APK at runtime.
 -dontwarn org.chromium.base.library_loader.NativeLibraries
 
+# Workaround for crbug/1002847. Methods of BaseGmsClient are incorrectly
+# removed even though they are required for the derived class GmsClient
+# to correctly implement Api$Client.
+# TODO: remove once crbug/1002847 resolved.
+-keep public class com.google.android.gms.common.internal.BaseGmsClient {
+  public void disconnect();
+  public void dump(java.lang.String,java.io.FileDescriptor,java.io.PrintWriter,java.lang.String[]);
+  public int getMinApkVersion();
+  public boolean requiresSignIn();
+}
+
 ################################################################################
 # ../../android_webview/support_library/boundary_interfaces/proguard.flags
 ################################################################################
@@ -362,6 +373,17 @@
   *** build() return null;
 }
 
+# Workaround for crbug/1002847. Methods of BaseGmsClient are incorrectly
+# removed even though they are required for the derived class GmsClient
+# to correctly implement Api$Client.
+# TODO: remove once crbug/1002847 resolved.
+-keep public class com.google.android.gms.common.internal.BaseGmsClient {
+  public void disconnect();
+  public void dump(java.lang.String,java.io.FileDescriptor,java.io.PrintWriter,java.lang.String[]);
+  public int getMinApkVersion();
+  public boolean requiresSignIn();
+}
+
 ################################################################################
 # ../../third_party/android_deps/support_mediarouter.flags
 ################################################################################

chrome/android/java/proguard.flags

@@ -70,3 +70,14 @@
   public <clinit>();
   *** build() return null;
 }
+
+# Workaround for crbug/1002847. Methods of BaseGmsClient are incorrectly
+# removed even though they are required for the derived class GmsClient
+# to correctly implement Api$Client.
+# TODO: remove once crbug/1002847 resolved.
+-keep public class com.google.android.gms.common.internal.BaseGmsClient {
+  public void disconnect();
+  public void dump(java.lang.String,java.io.FileDescriptor,java.io.PrintWriter,java.lang.String[]);
+  public int getMinApkVersion();
+  public boolean requiresSignIn();
+}