Set up field trials for SSL read/write buffer sizes.

net/socket/ssl_client_socket_impl.cc

Index: net/socket/ssl_client_socket_impl.cc
diff --git a/net/socket/ssl_client_socket_impl.cc b/net/socket/ssl_client_socket_impl.cc
index 80ff994982f2d3e804266d8623bae1dd2e90b0d4..76405869b08231a50f243c55df9d8a1100efa9b8 100644
--- a/net/socket/ssl_client_socket_impl.cc
+++ b/net/socket/ssl_client_socket_impl.cc
@@ -20,6 +20,7 @@
 #include "base/lazy_instance.h"
 #include "base/macros.h"
 #include "base/memory/singleton.h"
+#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/profiler/scoped_tracker.h"
@@ -929,10 +930,29 @@ int SSLClientSocketImpl::Init() {
   if (session)
     SSL_set_session(ssl_, session.get());
 
+  // Get read and write buffer sizes from field trials, if possible. If values
+  // not present, use default.  Also make sure values are in reasonable range.
+  int send_buffer_size;
+  if (!base::StringToInt(
+          base::FieldTrialList::FindFullName("SSLBufferSizeSend"),
+          &send_buffer_size)) {
+    send_buffer_size = KDefaultOpenSSLBufferSize;

[davidben, 2016/06/27 18:31:48]

(Haha. While you're here, do you mind fixing KDefaultOpenSSLBufferSize to be
kDefaultOpenSSLBufferSize?)

[mmenke, 2016/06/27 20:01:06]

I completely missed that!  Done.

+  }
+  send_buffer_size = std::max(send_buffer_size, 1000);
+  send_buffer_size = std::min(send_buffer_size, 2 * KDefaultOpenSSLBufferSize);
   send_buffer_ = new GrowableIOBuffer();
-  send_buffer_->SetCapacity(KDefaultOpenSSLBufferSize);
+  send_buffer_->SetCapacity(send_buffer_size);
+
+  int recv_buffer_size;
+  if (!base::StringToInt(
+          base::FieldTrialList::FindFullName("SSLBufferSizeRecv"),
+          &recv_buffer_size)) {
+    recv_buffer_size = KDefaultOpenSSLBufferSize;
+  }
+  recv_buffer_size = std::max(recv_buffer_size, 1000);
+  recv_buffer_size = std::min(recv_buffer_size, 2 * KDefaultOpenSSLBufferSize);
   recv_buffer_ = new GrowableIOBuffer();
-  recv_buffer_->SetCapacity(KDefaultOpenSSLBufferSize);
+  recv_buffer_->SetCapacity(recv_buffer_size);
 
   BIO* ssl_bio = NULL;