[Cronet] Make delaying sending request headers explicit in bidirectional stream

components/cronet/android/api/src/org/chromium/net/BidirectionalStream.java

Index: components/cronet/android/api/src/org/chromium/net/BidirectionalStream.java
diff --git a/components/cronet/android/api/src/org/chromium/net/BidirectionalStream.java b/components/cronet/android/api/src/org/chromium/net/BidirectionalStream.java
index d520f6e71d72ff9c6531851ab9d45fd7c2e7cf0a..246facfeab51fd44b629de6f6b8bae22f5763ad6 100644
--- a/components/cronet/android/api/src/org/chromium/net/BidirectionalStream.java
+++ b/components/cronet/android/api/src/org/chromium/net/BidirectionalStream.java
@@ -48,6 +48,7 @@ public abstract class BidirectionalStream {
         @StreamPriority private int mPriority = STREAM_PRIORITY_MEDIUM;
 
         private boolean mDisableAutoFlush;
+        private boolean mDelayHeadersUntilNextWrite;
 
         /**
          * Creates a builder for {@link BidirectionalStream} objects. All callbacks for
@@ -174,6 +175,21 @@ public abstract class BidirectionalStream {
         }
 
         /**
+         * Delays sending request headers until the next {@link write()} is invoked.
+         * This flag is currently only respected when QUIC is negotiated.
+         * When true, QUIC will send request header frame along with data frame(s)
+         * as a single packet when possible.
+         *
+         * @param delayHeadersUntilNextWrite if true, sending request headers will
+         *         be delayed until the next write() is invoked.
+         * @return the builder to facilitate chaining.
+         */
+        public Builder delayHeadersUntilNextWrite(boolean delayHeadersUntilNextWrite) {

[mef, 2016/05/23 14:57:26]

Does it have an effect if disableAutoFlush is false?

+            mDelayHeadersUntilNextWrite = delayHeadersUntilNextWrite;
+            return this;
+        }
+
+        /**
          * Creates a {@link BidirectionalStream} using configuration from this
          * {@link Builder}. The returned {@code BidirectionalStream} can then be started
          * by calling {@link BidirectionalStream#start}.
@@ -183,7 +199,7 @@ public abstract class BidirectionalStream {
          */
         public BidirectionalStream build() {
             return mCronetEngine.createBidirectionalStream(mUrl, mCallback, mExecutor, mHttpMethod,
-                    mRequestHeaders, mPriority, mDisableAutoFlush);
+                    mRequestHeaders, mPriority, mDisableAutoFlush, mDelayHeadersUntilNextWrite);
         }
     }