Remove @beta from APIs:

collect
- most Collectors (aside from BloomFilter and ImmutableRange*, as those whole classes are @beta (though I did remove the redundant @beta annotation from the Collector-returning methods for clarity))
- Maps: asConverter, immutableEnumMap
- MultimapBuilder
- Streams: stream(Iterable), concat

io
- ByteStreams: copy, toByteArray
- CharStreams: copy, toString
- Files: as(Char|Byte)(Source|Sink)

util.concurrent
- Futures: addCallback, getDone, getUnchecked, immediateCancelledFuture, immediateFailedFuture, immediateFuture
- ListeningScheduledExecutorService
- Uninterruptibles

other
- HtmlEscapers
- Splitter.splitToList
- Ticker

Fixes #3287
Fixes #3251 (aside from ImmutableRange*, but those whole classes are @beta, anyway)
Addresses the main concerns of #3285 but doesn't cover the broader request
Fixes #3340
Partially addresses #3239

RELNOTES=Removed `@Beta` from a number of frequently used APIs.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=232681253

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

@@ -408,7 +408,6 @@ private Iterator<String> splittingIterator(CharSequence sequence) {
    * @return an immutable list of the segments split from the parameter
    * @since 15.0
    */
-  @Beta
   public List<String> splitToList(CharSequence sequence) {
     checkNotNull(sequence);
 

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

@@ -14,7 +14,6 @@
 
 package com.google.common.base;
 
-import com.google.common.annotations.Beta;
 import com.google.common.annotations.GwtCompatible;
 
 /**
@@ -28,7 +27,6 @@
  * @since 10.0 (<a href="https://github.com/google/guava/wiki/Compatibility">mostly
  *     source-compatible</a> since 9.0)
  */
-@Beta
 @GwtCompatible
 public abstract class Ticker {
   /** Constructor for use by subclasses. */

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

@@ -139,7 +139,6 @@ V transform(Entry<K, V> entry) {
    * @since 14.0
    */
   @GwtCompatible(serializable = true)
-  @Beta
   public static <K extends Enum<K>, V> ImmutableMap<K, V> immutableEnumMap(
       Map<K, ? extends V> map) {
     if (map instanceof ImmutableEnumMap) {
@@ -1363,7 +1362,6 @@ public int hashCode() {
    *
    * @since 16.0
    */
-  @Beta
   public static <A, B> Converter<A, B> asConverter(final BiMap<A, B> bimap) {
     return new BiMapConverter<>(bimap);
   }

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

@@ -19,7 +19,6 @@
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.collect.CollectPreconditions.checkNonnegative;
 
-import com.google.common.annotations.Beta;
 import com.google.common.annotations.GwtCompatible;
 import com.google.common.base.Supplier;
 import java.io.Serializable;
@@ -61,7 +60,6 @@
  * @param <V0> An upper bound on the value type of the generated multimap.
  * @since 16.0
  */
-@Beta
 @GwtCompatible
 public abstract class MultimapBuilder<K0, V0> {
   /*

android/guava/src/com/google/common/html/HtmlEscapers.java

@@ -14,7 +14,6 @@
 
 package com.google.common.html;
 
-import com.google.common.annotations.Beta;
 import com.google.common.annotations.GwtCompatible;
 import com.google.common.escape.Escaper;
 import com.google.common.escape.Escapers;
@@ -35,7 +34,6 @@
  * @author David Beaumont
  * @since 15.0
  */
-@Beta
 @GwtCompatible
 public final class HtmlEscapers {
   /**

android/guava/src/com/google/common/io/ByteStreams.java

@@ -48,7 +48,6 @@
  * @author Colin Decker
  * @since 1.0
  */
-@Beta
 @GwtIncompatible
 public final class ByteStreams {
 
@@ -266,6 +265,7 @@ static byte[] toByteArray(InputStream in, long expectedSize) throws IOException
    * @since 20.0
    */
   @CanIgnoreReturnValue
+  @Beta
   public static long exhaust(InputStream in) throws IOException {
     long total = 0;
     long read;
@@ -280,6 +280,7 @@ public static long exhaust(InputStream in) throws IOException {
    * Returns a new {@link ByteArrayDataInput} instance to read from the {@code bytes} array from the
    * beginning.
    */
+  @Beta
   public static ByteArrayDataInput newDataInput(byte[] bytes) {
     return newDataInput(new ByteArrayInputStream(bytes));
   }
@@ -291,6 +292,7 @@ public static ByteArrayDataInput newDataInput(byte[] bytes) {
    * @throws IndexOutOfBoundsException if {@code start} is negative or greater than the length of
    *     the array
    */
+  @Beta
   public static ByteArrayDataInput newDataInput(byte[] bytes, int start) {
     checkPositionIndex(start, bytes.length);
     return newDataInput(new ByteArrayInputStream(bytes, start, bytes.length - start));
@@ -303,6 +305,7 @@ public static ByteArrayDataInput newDataInput(byte[] bytes, int start) {
    *
    * @since 17.0
    */
+  @Beta
   public static ByteArrayDataInput newDataInput(ByteArrayInputStream byteArrayInputStream) {
     return new ByteArrayDataInputStream(checkNotNull(byteArrayInputStream));
   }
@@ -453,6 +456,7 @@ public String readUTF() {
   }
 
   /** Returns a new {@link ByteArrayDataOutput} instance with a default size. */
+  @Beta
   public static ByteArrayDataOutput newDataOutput() {
     return newDataOutput(new ByteArrayOutputStream());
   }
@@ -463,6 +467,7 @@ public static ByteArrayDataOutput newDataOutput() {
    *
    * @throws IllegalArgumentException if {@code size} is negative
    */
+  @Beta
   public static ByteArrayDataOutput newDataOutput(int size) {
     // When called at high frequency, boxing size generates too much garbage,
     // so avoid doing that if we can.
@@ -484,6 +489,7 @@ public static ByteArrayDataOutput newDataOutput(int size) {
    *
    * @since 17.0
    */
+  @Beta
   public static ByteArrayDataOutput newDataOutput(ByteArrayOutputStream byteArrayOutputSteam) {
     return new ByteArrayDataOutputStream(checkNotNull(byteArrayOutputSteam));
   }
@@ -659,6 +665,7 @@ public String toString() {
    *
    * @since 14.0 (since 1.0 as com.google.common.io.NullOutputStream)
    */
+  @Beta
   public static OutputStream nullOutputStream() {
     return NULL_OUTPUT_STREAM;
   }
@@ -671,6 +678,7 @@ public static OutputStream nullOutputStream() {
    * @return a length-limited {@link InputStream}
    * @since 14.0 (since 1.0 as com.google.common.io.LimitInputStream)
    */
+  @Beta
   public static InputStream limit(InputStream in, long limit) {
     return new LimitedInputStream(in, limit);
   }
@@ -757,6 +765,7 @@ public long skip(long n) throws IOException {
    * @throws EOFException if this stream reaches the end before reading all the bytes.
    * @throws IOException if an I/O error occurs.
    */
+  @Beta
   public static void readFully(InputStream in, byte[] b) throws IOException {
     readFully(in, b, 0, b.length);
   }
@@ -773,6 +782,7 @@ public static void readFully(InputStream in, byte[] b) throws IOException {
    * @throws EOFException if this stream reaches the end before reading all the bytes.
    * @throws IOException if an I/O error occurs.
    */
+  @Beta
   public static void readFully(InputStream in, byte[] b, int off, int len) throws IOException {
     int read = read(in, b, off, len);
     if (read != len) {
@@ -790,6 +800,7 @@ public static void readFully(InputStream in, byte[] b, int off, int len) throws
    * @throws EOFException if this stream reaches the end before skipping all the bytes
    * @throws IOException if an I/O error occurs, or the stream does not support skipping
    */
+  @Beta
   public static void skipFully(InputStream in, long n) throws IOException {
     long skipped = skipUpTo(in, n);
     if (skipped < n) {
@@ -848,6 +859,7 @@ private static long skipSafely(InputStream in, long n) throws IOException {
    * @throws IOException if an I/O error occurs
    * @since 14.0
    */
+  @Beta
   @CanIgnoreReturnValue // some processors won't return a useful result
   public static <T> T readBytes(InputStream input, ByteProcessor<T> processor) throws IOException {
     checkNotNull(input);
@@ -883,6 +895,7 @@ public static <T> T readBytes(InputStream input, ByteProcessor<T> processor) thr
    * @return the number of bytes read
    * @throws IOException if an I/O error occurs
    */
+  @Beta
   @CanIgnoreReturnValue
   // Sometimes you don't care how many bytes you actually read, I guess.
   // (You know that it's either going to read len bytes or stop at EOF.)

android/guava/src/com/google/common/io/CharStreams.java

@@ -43,7 +43,6 @@
  * @author Colin Decker
  * @since 1.0
  */
-@Beta
 @GwtIncompatible
 public final class CharStreams {
 
@@ -193,6 +192,7 @@ private static StringBuilder toStringBuilder(Readable r) throws IOException {
    * @return a mutable {@link List} containing all the lines
    * @throws IOException if an I/O error occurs
    */
+  @Beta
   public static List<String> readLines(Readable r) throws IOException {
     List<String> result = new ArrayList<>();
     LineReader lineReader = new LineReader(r);
@@ -212,6 +212,7 @@ public static List<String> readLines(Readable r) throws IOException {
    * @throws IOException if an I/O error occurs
    * @since 14.0
    */
+  @Beta
   @CanIgnoreReturnValue // some processors won't return a useful result
   public static <T> T readLines(Readable readable, LineProcessor<T> processor) throws IOException {
     checkNotNull(readable);
@@ -233,6 +234,7 @@ public static <T> T readLines(Readable readable, LineProcessor<T> processor) thr
    *
    * @since 20.0
    */
+  @Beta
   @CanIgnoreReturnValue
   public static long exhaust(Readable readable) throws IOException {
     long total = 0;
@@ -254,6 +256,7 @@ public static long exhaust(Readable readable) throws IOException {
    * @throws EOFException if this stream reaches the end before skipping all the characters
    * @throws IOException if an I/O error occurs
    */
+  @Beta
   public static void skipFully(Reader reader, long n) throws IOException {
     checkNotNull(reader);
     while (n > 0) {
@@ -270,6 +273,7 @@ public static void skipFully(Reader reader, long n) throws IOException {
    *
    * @since 15.0
    */
+  @Beta
   public static Writer nullWriter() {
     return NullWriter.INSTANCE;
   }
@@ -338,6 +342,7 @@ public String toString() {
    * @param target the object to which output will be sent
    * @return a new Writer object, unless target is a Writer, in which case the target is returned
    */
+  @Beta
   public static Writer asWriter(Appendable target) {
     if (target instanceof Writer) {
       return (Writer) target;