[v8] Fix Chrome's "Experimental JavaScript" switch.

content/renderer/render_process_impl.cc

 // Copyright (c) 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 "content/renderer/render_process_impl.h"
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <objidl.h>
 #include <mlang.h>
 #endif
 
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
+#include "base/feature_list.h"
 #include "base/sys_info.h"
 #include "content/child/site_isolation_stats_gatherer.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/renderer/content_renderer_client.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
 #include "v8/include/v8.h"
 
+namespace {
+
+const base::Feature kV8_ES2015_TailCalls_Feature {
+  "V8_ES2015_TailCalls", base::FEATURE_DISABLED_BY_DEFAULT
+};
+
+const base::Feature kV8SerializeEagerFeature{"V8_Serialize_Eager",
+                                             base::FEATURE_DISABLED_BY_DEFAULT};
+
+const base::Feature kV8SerializeAgeCodeFeature{
+    "V8_Serialize_Age_Code", base::FEATURE_DISABLED_BY_DEFAULT};
+
+void SetV8FlagIfFeature(const base::Feature& feature, const char* v8_flag) {
+  if (base::FeatureList::IsEnabled(feature)) {
+    v8::V8::SetFlagsFromString(v8_flag, strlen(v8_flag));
+  }
+}
+
+void SetV8FlagIfHasSwitch(const char* switch_name, const char* v8_flag) {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(switch_name)) {
+    v8::V8::SetFlagsFromString(v8_flag, strlen(v8_flag));
+  }
+}
+
+}  // namespace
+
 namespace content {
 
 RenderProcessImpl::RenderProcessImpl()
     : enabled_bindings_(0) {
 #if defined(OS_WIN)
   // HACK:  See http://b/issue?id=1024307 for rationale.
   if (GetModuleHandle(L"LPK.DLL") == NULL) {
     // Makes sure lpk.dll is loaded by gdi32 to make sure ExtTextOut() works
     // when buffering into a EMF buffer for printing.
     typedef BOOL (__stdcall *GdiInitializeLanguagePack)(int LoadedShapingDLLs);
     GdiInitializeLanguagePack gdi_init_lpk =
         reinterpret_cast<GdiInitializeLanguagePack>(GetProcAddress(
             GetModuleHandle(L"GDI32.DLL"),
             "GdiInitializeLanguagePack"));
     DCHECK(gdi_init_lpk);
     if (gdi_init_lpk) {
       gdi_init_lpk(0);
     }
   }
 #endif
 
   if (base::SysInfo::IsLowEndDevice()) {
     std::string optimize_flag("--optimize-for-size");
     v8::V8::SetFlagsFromString(optimize_flag.c_str(),
                                static_cast<int>(optimize_flag.size()));
   }
 
+  SetV8FlagIfFeature(kV8_ES2015_TailCalls_Feature, "--harmony-tailcalls");
+  SetV8FlagIfFeature(kV8SerializeEagerFeature, "--serialize_eager");
+  SetV8FlagIfFeature(kV8SerializeAgeCodeFeature, "--serialize_age_code");
+  SetV8FlagIfHasSwitch(switches::kDisableJavaScriptHarmonyShipping,
+                       "--noharmony-shipping");
+  SetV8FlagIfHasSwitch(switches::kJavaScriptHarmony, "--harmony");
+  SetV8FlagIfHasSwitch(switches::kEnableWasm, "--expose-wasm");
+
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
+
   if (command_line.HasSwitch(switches::kJavaScriptFlags)) {
     std::string flags(
         command_line.GetSwitchValueASCII(switches::kJavaScriptFlags));
     v8::V8::SetFlagsFromString(flags.c_str(), static_cast<int>(flags.size()));
   }
 
   SiteIsolationStatsGatherer::SetEnabled(
       GetContentClient()->renderer()->ShouldGatherSiteIsolationStats());
 }
 
 RenderProcessImpl::~RenderProcessImpl() {
 #ifndef NDEBUG
   int count = blink::WebFrame::instanceCount();
   if (count)
     DLOG(ERROR) << "WebFrame LEAKED " << count << " TIMES";
 #endif
 
   GetShutDownEvent()->Signal();
 }
 
 void RenderProcessImpl::AddBindings(int bindings) {
   enabled_bindings_ |= bindings;
 }
 
 int RenderProcessImpl::GetEnabledBindings() const {
   return enabled_bindings_;
 }
 
 }  // namespace content