Make setting the user agent work with the zygote on linux.

webkit/glue/webkit_glue.cc

 // Copyright (c) 2011 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 "webkit/glue/webkit_glue.h"
 
 #if defined(OS_WIN)
 #include <objidl.h>
 #include <mlang.h>
 #elif defined(OS_POSIX) && !defined(OS_MACOSX)
@@ skipping 326 matching lines @@
 }
 
 namespace {
 
 class UserAgentState {
  public:
   UserAgentState();
   ~UserAgentState();
 
   void Set(const std::string& user_agent, bool overriding);
+  void Reset(const std::string& user_agent, bool overriding);
   const std::string& Get(const GURL& url) const;
 
  private:
   mutable std::string user_agent_;
   // The UA string when we're pretending to be Mac Safari.
   mutable std::string mimic_mac_safari_user_agent_;
 
   mutable bool user_agent_requested_;
   bool user_agent_is_overridden_;
 
@@ skipping 11 matching lines @@
 }
 
 void UserAgentState::Set(const std::string& user_agent, bool overriding) {
   base::AutoLock auto_lock(lock_);
   if (user_agent == user_agent_) {
     // We allow the user agent to be set multiple times as long as it
     // is set to the same value, in order to simplify unit testing
     // given g_user_agent is a global.
     return;
   }
-  DCHECK(!user_agent.empty());
   DCHECK(!user_agent_requested_) << "Setting the user agent after someone has "
       "already requested it can result in unexpected behavior.";
+  lock_.Release();
+  UserAgentState::Reset(user_agent, overriding);
+  lock_.Acquire();
+}
+
+void UserAgentState::Reset(const std::string& user_agent, bool overriding) {
+  base::AutoLock auto_lock(lock_);
+  DCHECK(!user_agent.empty());
   user_agent_is_overridden_ = overriding;
   user_agent_ = user_agent;
 }
 
 const std::string& UserAgentState::Get(const GURL& url) const {
   base::AutoLock auto_lock(lock_);
   user_agent_requested_ = true;
 
   DCHECK(!user_agent_.empty());
 
@@ skipping 19 matching lines @@
 }
 
 base::LazyInstance<UserAgentState> g_user_agent(base::LINKER_INITIALIZED);
 
 }  // namespace
 
 void SetUserAgent(const std::string& user_agent, bool overriding) {
   g_user_agent.Get().Set(user_agent, overriding);
 }
 
+void ResetUserAgent(const std::string& user_agent, bool overriding) {
+  g_user_agent.Get().Reset(user_agent, overriding);
+}
+
 const std::string& GetUserAgent(const GURL& url) {
   return g_user_agent.Get().Get(url);
 }
 
 void SetForcefullyTerminatePluginProcess(bool value) {
   g_forcefully_terminate_plugin_process = value;
 }
 
 bool ShouldForcefullyTerminatePluginProcess() {
   return g_forcefully_terminate_plugin_process;
 }
 
 WebCanvas* ToWebCanvas(skia::PlatformCanvas* canvas) {
 #if WEBKIT_USING_SKIA
   return canvas;
 #elif WEBKIT_USING_CG
   return skia::GetBitmapContext(skia::GetTopDevice(*canvas));
 #else
   NOTIMPLEMENTED();
   return NULL;
 #endif
 }
 
 int GetGlyphPageCount() {
   return WebGlyphCache::pageCount();
 }
 
 } // namespace webkit_glue