Remove obsolete GWT-RPC logging code.

android/guava/src/com/google/common/base/Platform.java

@@ -107,6 +107,4 @@ public boolean isPcreLike() {
       return true;
     }
   }
-
-  static void checkGwtRpcEnabled() {}
 }

android/guava/src/com/google/common/collect/Platform.java

@@ -129,7 +129,5 @@ static int reduceExponentIfGwt(int exponent) {
     return exponent;
   }
 
-  static void checkGwtRpcEnabled() {}
-
   private Platform() {}
 }

guava-gwt/src-super/com/google/common/base/super/com/google/common/base/Platform.java

@@ -64,16 +64,5 @@ static boolean patternCompilerIsPcreLike() {
     throw new UnsupportedOperationException();
   }
 
-  /*
-   * We will eventually disable GWT-RPC on the server side, but we'll leave it nominally enabled on
-   * the client side. There's little practical difference: If it's disabled on the server, it won't
-   * work. It's just a matter of how quickly it fails. I'm not sure if failing on the client would
-   * be better or not, but it's harder: GWT's System.getProperty reads from a different property
-   * list than Java's, so anyone who needs to reenable GWT-RPC in an emergency would have to figure
-   * out how to set both properties. It's easier to have to set only one, and it might as well be
-   * the Java property, since Guava already reads another Java property.
-   */
-  static void checkGwtRpcEnabled() {}
-
   private Platform() {}
 }

guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/Platform.java

@@ -117,16 +117,5 @@ static int reduceExponentIfGwt(int exponent) {
     return exponent / 2;
   }
 
-  /*
-   * We will eventually disable GWT-RPC on the server side, but we'll leave it nominally enabled on
-   * the client side. There's little practical difference: If it's disabled on the server, it won't
-   * work. It's just a matter of how quickly it fails. I'm not sure if failing on the client would
-   * be better or not, but it's harder: GWT's System.getProperty reads from a different property
-   * list than Java's, so anyone who needs to reenable GWT-RPC in an emergency would have to figure
-   * out how to set both properties. It's easier to have to set only one, and it might as well be
-   * the Java property, since Guava already reads another Java property.
-   */
-  static void checkGwtRpcEnabled() {}
-
   private Platform() {}
 }

guava/src/com/google/common/base/Platform.java

@@ -102,25 +102,4 @@ public boolean isPcreLike() {
       return true;
     }
   }
-
-  static void checkGwtRpcEnabled() {
-    String propertyName = "guava.gwt.emergency_reenable_rpc";
-
-    if (!Boolean.parseBoolean(System.getProperty(propertyName, "false"))) {
-      throw new UnsupportedOperationException(
-          Strings.lenientFormat(
-              "We are removing GWT-RPC support for Guava types. You can temporarily reenable"
-                  + " support by setting the system property %s to true. For more about system"
-                  + " properties, see %s. For more about Guava's GWT-RPC support, see %s.",
-              propertyName,
-              "https://stackoverflow.com/q/5189914/28465",
-              "https://groups.google.com/d/msg/guava-announce/zHZTFg7YF3o/rQNnwdHeEwAJ"));
-    }
-    logger.log(
-        java.util.logging.Level.WARNING,
-        "Later in 2020, we will remove GWT-RPC support for Guava types. You are seeing this"
-            + " warning because you are sending a Guava type over GWT-RPC, which will break. You"
-            + " can identify which type by looking at the class name in the attached stack trace.",
-        new Throwable());
-  }
 }

guava/src/com/google/common/collect/Platform.java

@@ -138,26 +138,5 @@ static int reduceExponentIfGwt(int exponent) {
     return exponent;
   }
 
-  static void checkGwtRpcEnabled() {
-    String propertyName = "guava.gwt.emergency_reenable_rpc";
-
-    if (!Boolean.parseBoolean(System.getProperty(propertyName, "false"))) {
-      throw new UnsupportedOperationException(
-          com.google.common.base.Strings.lenientFormat(
-              "We are removing GWT-RPC support for Guava types. You can temporarily reenable"
-                  + " support by setting the system property %s to true. For more about system"
-                  + " properties, see %s. For more about Guava's GWT-RPC support, see %s.",
-              propertyName,
-              "https://stackoverflow.com/q/5189914/28465",
-              "https://groups.google.com/d/msg/guava-announce/zHZTFg7YF3o/rQNnwdHeEwAJ"));
-    }
-    logger.log(
-        java.util.logging.Level.WARNING,
-        "Later in 2020, we will remove GWT-RPC support for Guava types. You are seeing this"
-            + " warning because you are sending a Guava type over GWT-RPC, which will break. You"
-            + " can identify which type by looking at the class name in the attached stack trace.",
-        new Throwable());
-  }
-
   private Platform() {}
 }