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

6 files changed, 44 insertions, 43 deletions

diff --git a/webkit/appcache/web_application_cache_host_impl.cc b/webkit/appcache/web_application_cache_host_impl.cc
index f65bed6..76c75c19 100644
--- a/webkit/appcache/web_application_cache_host_impl.cc
+++ b/webkit/appcache/web_application_cache_host_impl.cc
@@ -6,9 +6,9 @@
 
 #include "base/compiler_specific.h"
 #include "base/id_map.h"
+#include "base/lazy_instance.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
-#include "base/singleton.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebDataSource.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebFrame.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebURL.h"
@@ -29,6 +29,7 @@ namespace appcache {
 namespace {
 
 typedef IDMap<WebApplicationCacheHostImpl> HostsMap;
+static base::LazyInstance<HostsMap> g_hosts_map(base::LINKER_INITIALIZED);
 
 // Note: the order of the elements in this array must match those
 // of the EventID enum in appcache_interfaces.h.
@@ -45,14 +46,10 @@ GURL ClearUrlRef(const GURL& url) {
   return url.ReplaceComponents(replacements);
 }
 
-HostsMap* all_hosts() {
-  return Singleton<HostsMap>::get();
-}
-
 }  // anon namespace
 
 WebApplicationCacheHostImpl* WebApplicationCacheHostImpl::FromId(int id) {
-  return all_hosts()->Lookup(id);
+  return g_hosts_map.Get().Lookup(id);
 }
 
 WebApplicationCacheHostImpl* WebApplicationCacheHostImpl::FromFrame(
@@ -71,7 +68,7 @@ WebApplicationCacheHostImpl::WebApplicationCacheHostImpl(
     AppCacheBackend* backend)
     : client_(client),
       backend_(backend),
-      ALLOW_THIS_IN_INITIALIZER_LIST(host_id_(all_hosts()->Add(this))),
+      ALLOW_THIS_IN_INITIALIZER_LIST(host_id_(g_hosts_map.Get().Add(this))),
       has_status_(false),
       status_(UNCACHED),
       has_cached_status_(false),
@@ -86,7 +83,7 @@ WebApplicationCacheHostImpl::WebApplicationCacheHostImpl(
 
 WebApplicationCacheHostImpl::~WebApplicationCacheHostImpl() {
   backend_->UnregisterHost(host_id_);
-  all_hosts()->Remove(host_id_);
+  g_hosts_map.Get().Remove(host_id_);
 }
 
 void WebApplicationCacheHostImpl::OnCacheSelected(
diff --git a/webkit/blob/deletable_file_reference.cc b/webkit/blob/deletable_file_reference.cc
index 87ef4cc..7a5cfac 100644
--- a/webkit/blob/deletable_file_reference.cc
+++ b/webkit/blob/deletable_file_reference.cc
@@ -7,27 +7,25 @@
 #include <map>
 #include "base/file_util.h"
 #include "base/file_util_proxy.h"
+#include "base/lazy_instance.h"
 #include "base/message_loop_proxy.h"
-#include "base/singleton.h"
 
 namespace webkit_blob {
 
 namespace {
 
 typedef std::map<FilePath, DeletableFileReference*> DeleteableFileMap;
-
-DeleteableFileMap* map() {
-  return Singleton<DeleteableFileMap>::get();
-}
+static base::LazyInstance<DeleteableFileMap> g_deletable_file_map(
+    base::LINKER_INITIALIZED);
 
 }  // namespace
 
 // static
 scoped_refptr<DeletableFileReference> DeletableFileReference::Get(
     const FilePath& path) {
-  DeleteableFileMap::iterator found = map()->find(path);
+  DeleteableFileMap::iterator found = g_deletable_file_map.Get().find(path);
   DeletableFileReference* reference =
-      (found == map()->end()) ? NULL : found->second;
+      (found == g_deletable_file_map.Get().end()) ? NULL : found->second;
   return scoped_refptr<DeletableFileReference>(reference);
 }
 
@@ -36,7 +34,7 @@ scoped_refptr<DeletableFileReference> DeletableFileReference::GetOrCreate(
     const FilePath& path, base::MessageLoopProxy* file_thread) {
   DCHECK(file_thread);
   typedef std::pair<DeleteableFileMap::iterator, bool> InsertResult;
-  InsertResult result = map()->insert(
+  InsertResult result = g_deletable_file_map.Get().insert(
       DeleteableFileMap::value_type(path, NULL));
   if (result.second == false)
     return scoped_refptr<DeletableFileReference>(result.first->second);
@@ -51,12 +49,12 @@ scoped_refptr<DeletableFileReference> DeletableFileReference::GetOrCreate(
 DeletableFileReference::DeletableFileReference(
     const FilePath& path, base::MessageLoopProxy* file_thread)
     : path_(path), file_thread_(file_thread) {
-  DCHECK(map()->find(path_)->second == NULL);
+  DCHECK(g_deletable_file_map.Get().find(path_)->second == NULL);
 }
 
 DeletableFileReference::~DeletableFileReference() {
-  DCHECK(map()->find(path_)->second == this);
-  map()->erase(path_);
+  DCHECK(g_deletable_file_map.Get().find(path_)->second == this);
+  g_deletable_file_map.Get().erase(path_);
   base::FileUtilProxy::Delete(file_thread_, path_, false /* recursive */, NULL);
 }
 
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) {