Make members of Singleton<T> private and only visible to the singleton type. This enforces that the Singleton<T> pattern can only be used within classes which want singleton-ness.

As part of this CL I have also fixed up files which got missed in my previous CLs to use a GetInstance() method and use Singleton<T> from the source file.

There are a small number of places where I have also switched to LazyInstance as that was more appropriate for types used in a single source file.

BUG=65298
TEST=all existing tests should continue to pass.

Review URL: http://codereview.chromium.org/5682008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@69107 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 30 insertions, 24 deletions

diff --git a/webkit/glue/plugins/pepper_graphics_3d.cc b/webkit/glue/plugins/pepper_graphics_3d.cc
index 34551da..3a5f129 100644
--- a/webkit/glue/plugins/pepper_graphics_3d.cc
+++ b/webkit/glue/plugins/pepper_graphics_3d.cc
@@ -5,7 +5,7 @@
 #include "webkit/glue/plugins/pepper_graphics_3d.h"
 
 #include "gpu/command_buffer/common/command_buffer.h"
-#include "base/singleton.h"
+#include "base/lazy_instance.h"
 #include "base/thread_local.h"
 #include "ppapi/c/dev/ppb_graphics_3d_dev.h"
 #include "webkit/glue/plugins/pepper_common.h"
@@ -15,10 +15,8 @@ namespace pepper {
 
 namespace {
 
-struct CurrentContextTag {};
-typedef Singleton<base::ThreadLocalPointer<Graphics3D>,
-    DefaultSingletonTraits<base::ThreadLocalPointer<Graphics3D> >,
-    CurrentContextTag> CurrentContextKey;
+static base::LazyInstance<base::ThreadLocalPointer<Graphics3D> >
+    g_current_context_key(base::LINKER_INITIALIZED);
 
 // Size of the transfer buffer.
 enum { kTransferBufferSize = 512 * 1024 };
@@ -138,11 +136,11 @@ const PPB_Graphics3D_Dev* Graphics3D::GetInterface() {
 }
 
 Graphics3D* Graphics3D::GetCurrent() {
-  return CurrentContextKey::get()->Get();
+  return g_current_context_key.Get().Get();
 }
 
 void Graphics3D::ResetCurrent() {
-  CurrentContextKey::get()->Set(NULL);
+  g_current_context_key.Get().Set(NULL);
 }
 
 Graphics3D* Graphics3D::AsGraphics3D() {
@@ -205,7 +203,7 @@ bool Graphics3D::MakeCurrent() {
   if (!platform_context_.get())
     return false;
 
-  CurrentContextKey::get()->Set(this);
+  g_current_context_key.Get().Set(this);
 
   // TODO(apatrick): Return false on context lost.
   return true;
diff --git a/webkit/glue/plugins/pepper_resource_tracker.cc b/webkit/glue/plugins/pepper_resource_tracker.cc
index 997ef63..9623e98 100644
--- a/webkit/glue/plugins/pepper_resource_tracker.cc
+++ b/webkit/glue/plugins/pepper_resource_tracker.cc
@@ -7,11 +7,15 @@
 #include <limits>
 #include <set>
 
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/rand_util.h"
 #include "ppapi/c/pp_resource.h"
 #include "webkit/glue/plugins/pepper_resource.h"
 
+static base::LazyInstance<pepper::ResourceTracker> g_resource_tracker(
+    base::LINKER_INITIALIZED);
+
 namespace pepper {
 
 scoped_refptr<Resource> ResourceTracker::GetResource(PP_Resource res) const {
@@ -36,7 +40,7 @@ ResourceTracker::~ResourceTracker() {
 ResourceTracker* ResourceTracker::Get() {
   if (singleton_override_)
     return singleton_override_;
-  return Singleton<ResourceTracker>::get();
+  return g_resource_tracker.Pointer();
 }
 
 PP_Resource ResourceTracker::AddResource(Resource* resource) {
diff --git a/webkit/glue/plugins/pepper_resource_tracker.h b/webkit/glue/plugins/pepper_resource_tracker.h
index 09ff976..0e463b4 100644
--- a/webkit/glue/plugins/pepper_resource_tracker.h
+++ b/webkit/glue/plugins/pepper_resource_tracker.h
@@ -12,11 +12,14 @@
 #include "base/gtest_prod_util.h"
 #include "base/hash_tables.h"
 #include "base/ref_counted.h"
-#include "base/singleton.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_module.h"
 #include "ppapi/c/pp_resource.h"
 
+namespace base {
+template <typename T> struct DefaultLazyInstanceTraits;
+}
+
 namespace pepper {
 
 class PluginInstance;
@@ -91,7 +94,7 @@ class ResourceTracker {
   PluginInstance* GetInstance(PP_Instance instance);
 
  private:
-  friend struct DefaultSingletonTraits<ResourceTracker>;
+  friend struct base::DefaultLazyInstanceTraits<ResourceTracker>;
   friend class Resource;
   friend class ResourceTrackerTest;
 
diff --git a/webkit/glue/webkit_glue.cc b/webkit/glue/webkit_glue.cc
index 350ba29..45944fc 100644
--- a/webkit/glue/webkit_glue.cc
+++ b/webkit/glue/webkit_glue.cc
@@ -11,9 +11,9 @@
 #include <sys/utsname.h>
 #endif
 
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/scoped_ptr.h"
-#include "base/singleton.h"
 #include "base/string_piece.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
@@ -356,10 +356,11 @@ struct UserAgentState {
   bool user_agent_is_overridden;
 };
 
-Singleton<UserAgentState> g_user_agent;
+static base::LazyInstance<UserAgentState> g_user_agent(
+    base::LINKER_INITIALIZED);
 
 void SetUserAgentToDefault() {
-  BuildUserAgent(false, &g_user_agent->user_agent);
+  BuildUserAgent(false, &g_user_agent.Get().user_agent);
 }
 
 }  // namespace
@@ -367,31 +368,31 @@ void SetUserAgentToDefault() {
 void SetUserAgent(const std::string& new_user_agent) {
   // If you combine this with the previous line, the function only works the
   // first time.
-  DCHECK(!g_user_agent->user_agent_requested) <<
+  DCHECK(!g_user_agent.Get().user_agent_requested) <<
       "Setting the user agent after someone has "
       "already requested it can result in unexpected behavior.";
-  g_user_agent->user_agent_is_overridden = true;
-  g_user_agent->user_agent = new_user_agent;
+  g_user_agent.Get().user_agent_is_overridden = true;
+  g_user_agent.Get().user_agent = new_user_agent;
 }
 
 const std::string& GetUserAgent(const GURL& url) {
-  if (g_user_agent->user_agent.empty())
+  if (g_user_agent.Get().user_agent.empty())
     SetUserAgentToDefault();
-  g_user_agent->user_agent_requested = true;
-  if (!g_user_agent->user_agent_is_overridden) {
+  g_user_agent.Get().user_agent_requested = true;
+  if (!g_user_agent.Get().user_agent_is_overridden) {
     // Workarounds for sites that use misguided UA sniffing.
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
     if (MatchPattern(url.host(), "*.mail.yahoo.com")) {
       // mail.yahoo.com is ok with Windows Chrome but not Linux Chrome.
       // http://bugs.chromium.org/11136
       // TODO(evanm): remove this if Yahoo fixes their sniffing.
-      if (g_user_agent->mimic_windows_user_agent.empty())
-        BuildUserAgent(true, &g_user_agent->mimic_windows_user_agent);
-      return g_user_agent->mimic_windows_user_agent;
+      if (g_user_agent.Get().mimic_windows_user_agent.empty())
+        BuildUserAgent(true, &g_user_agent.Get().mimic_windows_user_agent);
+      return g_user_agent.Get().mimic_windows_user_agent;
     }
 #endif
   }
-  return g_user_agent->user_agent;
+  return g_user_agent.Get().user_agent;
 }
 
 void SetForcefullyTerminatePluginProcess(bool value) {