Enable QUIC for proxies based on Finch config and command line switch.

chrome/browser/io_thread.h

Index: chrome/browser/io_thread.h
diff --git a/chrome/browser/io_thread.h b/chrome/browser/io_thread.h
index 3fbbe9ea0475a77def068621e0572f89d21a0c48..55c07a5d88b2bc41bb599e385466f350f263fe10 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -182,6 +182,7 @@ class IOThread : public content::BrowserThreadDelegate {
     Optional<double> alternate_protocol_probability_threshold;
 
     Optional<bool> enable_quic;
+    Optional<bool> enable_quic_for_proxies;
     Optional<bool> enable_quic_port_selection;
     Optional<bool> quic_always_require_handshake_confirmation;
     Optional<bool> quic_disable_connection_pooling;
@@ -236,6 +237,10 @@ class IOThread : public content::BrowserThreadDelegate {
 
   base::TimeTicks creation_time() const;
 
+  // Returns true if QUIC should be enabled for data reduction proxy, either as
+  // a result of a field trial or a command line flag.
+  static bool ShouldEnableQuicForDataReductionProxy();
+
  private:
   // Map from name to value for all parameters associate with a field trial.
   typedef std::map<std::string, std::string> VariationParameters;
@@ -330,6 +335,12 @@ class IOThread : public content::BrowserThreadDelegate {
       const base::CommandLine& command_line,
       base::StringPiece quic_trial_group);
 
+  // Returns true if QUIC should be enabled for proxies, either as a result
+  // of a field trial or a command line flag.
+  static bool ShouldEnableQuicForProxies(
+      const base::CommandLine& command_line,
+      base::StringPiece quic_trial_group);
+
   // Returns true if the selection of the ephemeral port in bind() should be
   // performed by Chromium, and false if the OS should select the port.  The OS
   // option is used to prevent Windows from posting a security security warning