[Sync] Make compression from client to server as default.

BUG=657911

Review-Url: https://codereview.chromium.org/2703593006
Cr-Commit-Position: refs/heads/master@{#451909}

components/sync/engine/net/http_bridge.cc

@@ -63,10 +63,6 @@ void RecordSyncResponseContentLengthHistograms(
 
 }  // namespace
 
-// Enables compression of messages from client to server.
-const base::Feature kSyncClientToServerCompression{
-    "EnableSyncClientToServerCompression", base::FEATURE_DISABLED_BY_DEFAULT};
-
 HttpBridgeFactory::HttpBridgeFactory(
     const scoped_refptr<net::URLRequestContextGetter>& request_context_getter,
     const NetworkTimeUpdateCallback& network_time_update_callback,
@@ -247,12 +243,8 @@ void HttpBridge::MakeAsynchronousPost() {
   fetch_state_.url_poster->SetExtraRequestHeaders(extra_headers_);
 
   std::string request_to_send;
-  if (base::FeatureList::IsEnabled(kSyncClientToServerCompression)) {
-    compression::GzipCompress(request_content_, &request_to_send);
-    fetch_state_.url_poster->AddExtraRequestHeader("Content-Encoding: gzip");
-  } else {
-    request_to_send = request_content_;
-  }
+  compression::GzipCompress(request_content_, &request_to_send);
+  fetch_state_.url_poster->AddExtraRequestHeader("Content-Encoding: gzip");
   fetch_state_.url_poster->SetUploadData(content_type_, request_to_send);
   RecordSyncRequestContentLengthHistograms(request_to_send.size(),
                                            request_content_.size());

components/sync/engine/net/http_bridge.h

@@ -11,7 +11,6 @@
 #include <string>
 
 #include "base/compiler_specific.h"
-#include "base/feature_list.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
@@ -37,7 +36,6 @@ class URLFetcher;
 namespace syncer {
 
 class CancelationSignal;
-extern const base::Feature kSyncClientToServerCompression;
 
 // A bridge between the syncer and Chromium HTTP layers.
 // Provides a way for the sync backend to use Chromium directly for HTTP

components/sync/engine/net/http_bridge_unittest.cc

@@ -10,7 +10,6 @@
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/stringprintf.h"
-#include "base/test/scoped_feature_list.h"
 #include "base/threading/thread.h"
 #include "build/build_config.h"
 #include "components/sync/base/cancelation_signal.h"
@@ -226,41 +225,15 @@ TEST_F(MAYBE_SyncHttpBridgeTest, TestMakeSynchronousPostShunted) {
             std::string(http_bridge->GetResponseContent()));
 }
 
-// Full round-trip test of the HttpBridge, using default UA string and
-// no request cookies.
-TEST_F(MAYBE_SyncHttpBridgeTest, TestMakeSynchronousPostLiveWithPayload) {
-  ASSERT_TRUE(test_server_.Start());
-
-  scoped_refptr<HttpBridge> http_bridge(BuildBridge());
-
-  std::string payload = "this should be echoed back";
-  GURL echo = test_server_.GetURL("/echo");
-  http_bridge->SetURL(echo.spec().c_str(), echo.IntPort());
-  http_bridge->SetPostPayload("application/x-www-form-urlencoded",
-                              payload.length() + 1, payload.c_str());
-  int os_error = 0;
-  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);
-
-  EXPECT_EQ(payload.length() + 1,
-            static_cast<size_t>(http_bridge->GetResponseContentLength()));
-  EXPECT_EQ(payload, std::string(http_bridge->GetResponseContent()));
-}
-
 // Full round-trip test of the HttpBridge with compressed data, check if the
 // data is correctly compressed.
 TEST_F(MAYBE_SyncHttpBridgeTest, CompressedRequestPayloadCheck) {
-  base::test::ScopedFeatureList scoped_feature_list;
-  scoped_feature_list.InitAndEnableFeature(kSyncClientToServerCompression);
-
   ASSERT_TRUE(test_server_.Start());
 
   scoped_refptr<HttpBridge> http_bridge(BuildBridge());
 
-  std::string payload = "this should be echoed back";
+  std::string payload =
+      "this should be echoed back, this should be echoed back.";
   GURL echo = test_server_.GetURL("/echo");
   http_bridge->SetURL(echo.spec().c_str(), echo.IntPort());
   http_bridge->SetPostPayload("application/x-www-form-urlencoded",
@@ -272,7 +245,8 @@ TEST_F(MAYBE_SyncHttpBridgeTest, CompressedRequestPayloadCheck) {
   EXPECT_EQ(200, response_code);
   EXPECT_EQ(0, os_error);
 
-  EXPECT_NE(payload.length() + 1,
+  // Verifying compression, check if the actual payload is compressed correctly.
+  EXPECT_GT(payload.length(),
             static_cast<size_t>(http_bridge->GetResponseContentLength()));
   std::string compressed_payload(http_bridge->GetResponseContent(),
                                  http_bridge->GetResponseContentLength());
@@ -285,9 +259,6 @@ TEST_F(MAYBE_SyncHttpBridgeTest, CompressedRequestPayloadCheck) {
 // fields("Content-Encoding" ,"Accept-Encoding" and user agent) are set
 // correctly.
 TEST_F(MAYBE_SyncHttpBridgeTest, CompressedRequestHeaderCheck) {
-  base::test::ScopedFeatureList scoped_feature_list;
-  scoped_feature_list.InitAndEnableFeature(kSyncClientToServerCompression);
-
   ASSERT_TRUE(test_server_.Start());
 
   scoped_refptr<HttpBridge> http_bridge(BuildBridge());
@@ -318,35 +289,6 @@ TEST_F(MAYBE_SyncHttpBridgeTest, CompressedRequestHeaderCheck) {
                 "%s: %s", net::HttpRequestHeaders::kUserAgent, kUserAgent)));
 }
 
-// Full round-trip test of the HttpBridge.
-TEST_F(MAYBE_SyncHttpBridgeTest, TestMakeSynchronousPostLiveComprehensive) {
-  ASSERT_TRUE(test_server_.Start());
-
-  scoped_refptr<HttpBridge> http_bridge(BuildBridge());
-
-  GURL echo_header = test_server_.GetURL("/echoall");
-  http_bridge->SetURL(echo_header.spec().c_str(), echo_header.IntPort());
-
-  std::string test_payload = "###TEST PAYLOAD###";
-  http_bridge->SetPostPayload("text/html", test_payload.length() + 1,
-                              test_payload.c_str());
-
-  int os_error = 0;
-  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::kUserAgent, kUserAgent)));
-  EXPECT_NE(std::string::npos, response.find(test_payload.c_str()));
-}
-
 TEST_F(MAYBE_SyncHttpBridgeTest, TestExtraRequestHeaders) {
   ASSERT_TRUE(test_server_.Start());
 
@@ -372,7 +314,6 @@ TEST_F(MAYBE_SyncHttpBridgeTest, TestExtraRequestHeaders) {
                        http_bridge->GetResponseContentLength());
 
   EXPECT_NE(std::string::npos, response.find("fnord"));
-  EXPECT_NE(std::string::npos, response.find(test_payload.c_str()));
 }
 
 TEST_F(MAYBE_SyncHttpBridgeTest, TestResponseHeader) {

components/sync/engine_impl/commit.cc

@@ -6,12 +6,10 @@
 
 #include <utility>
 
-#include "base/feature_list.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/rand_util.h"
 #include "base/trace_event/trace_event.h"
 #include "components/sync/base/data_type_histogram.h"
-#include "components/sync/engine/net/http_bridge.h"
 #include "components/sync/engine_impl/commit_processor.h"
 #include "components/sync/engine_impl/commit_util.h"
 #include "components/sync/engine_impl/cycle/sync_cycle.h"
@@ -79,9 +77,7 @@ Commit* Commit::Init(ModelTypeSet requested_types,
   commit_message->set_cache_guid(cache_guid);
 
   // Set padding to mitigate CRIME attack.
-  if (base::FeatureList::IsEnabled(syncer::kSyncClientToServerCompression)) {
-    commit_message->set_padding(RandASCIIString(kPaddingSize));
-  }
+  commit_message->set_padding(RandASCIIString(kPaddingSize));
 
   // Set extensions activity if bookmark commits are present.
   ExtensionsActivity::Records extensions_activity_buffer;