[Sync] Make chrome sync response compression as default

sync/internal_api/http_bridge_unittest.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/bit_cast.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/stringprintf.h"
@@ skipping 295 matching lines @@
   int response_code = 0;
   bool success = http_bridge->MakeSynchronousPost(&os_error, &response_code);
   EXPECT_TRUE(success);
   EXPECT_EQ(200, response_code);
   EXPECT_EQ(0, os_error);
 
   std::string response(http_bridge->GetResponseContent(),
                        http_bridge->GetResponseContentLength());
   EXPECT_EQ(std::string::npos, response.find("Cookie:"));
   EXPECT_NE(std::string::npos,
-            response.find(base::StringPrintf(
-                "%s: %s", net::HttpRequestHeaders::kAcceptEncoding,
-                "deflate")));
-  EXPECT_NE(std::string::npos,
             response.find(base::StringPrintf("%s: %s",
                           net::HttpRequestHeaders::kUserAgent, kUserAgent)));
   EXPECT_NE(std::string::npos, response.find(test_payload.c_str()));
 }
 
 TEST_F(MAYBE_SyncHttpBridgeTest, TestExtraRequestHeaders) {
   ASSERT_TRUE(test_server_.Start());
 
   scoped_refptr<HttpBridge> http_bridge(BuildBridge());
 
@@ skipping 256 matching lines @@
 
   // Sync thread: Finally run the posted task, only to find that our
   // HttpBridgeFactory has been neutered.  Should not crash.
   factory->Init("TestUserAgent", BindToTrackerCallback());
 
   // At this point, attempting to use the factory would trigger a crash.  Both
   // this test and the real world code should make sure this never happens.
 }
 
 }  // namespace syncer