De-coupled resource references by plugin from Resource object's refcount. Made so that ResourceTracker keeps the refs-by-plugin count, and when the ppapi plugin releases the last reference, it UnRefs the resource.

TEST=none
BUG=none

Review URL: http://codereview.chromium.org/2871027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@53098 0039d316-1c4b-4281-b951-d872f2087c98

19 files changed, 220 insertions, 194 deletions

diff --git a/webkit/glue/plugins/pepper_buffer.cc b/webkit/glue/plugins/pepper_buffer.cc
index 4d94975..1c0bdd8 100644
--- a/webkit/glue/plugins/pepper_buffer.cc
+++ b/webkit/glue/plugins/pepper_buffer.cc
@@ -27,18 +27,17 @@ PP_Resource Create(PP_Module module_id, int32_t size) {
   scoped_refptr<Buffer> buffer(new Buffer(module));
   if (!buffer->Init(size))
     return NULL;
-  buffer->AddRef();  // AddRef for the caller.
 
-  return buffer->GetResource();
+  return buffer->GetReference();
 }
 
 bool IsBuffer(PP_Resource resource) {
-  return !!Resource::GetAs<Buffer>(resource).get();
+  return !!Resource::GetAs<Buffer>(resource);
 }
 
 bool Describe(PP_Resource resource, int32_t* size_in_bytes) {
   scoped_refptr<Buffer> buffer(Resource::GetAs<Buffer>(resource));
-  if (!buffer.get())
+  if (!buffer)
     return false;
   buffer->Describe(size_in_bytes);
   return true;
@@ -46,7 +45,7 @@ bool Describe(PP_Resource resource, int32_t* size_in_bytes) {
 
 void* Map(PP_Resource resource) {
   scoped_refptr<Buffer> buffer(Resource::GetAs<Buffer>(resource));
-  if (!buffer.get())
+  if (!buffer)
     return NULL;
   return buffer->Map();
 }
diff --git a/webkit/glue/plugins/pepper_device_context_2d.cc b/webkit/glue/plugins/pepper_device_context_2d.cc
index 4f77751d..45ed9ee 100644
--- a/webkit/glue/plugins/pepper_device_context_2d.cc
+++ b/webkit/glue/plugins/pepper_device_context_2d.cc
@@ -73,14 +73,11 @@ PP_Resource Create(PP_Module module_id,
   scoped_refptr<DeviceContext2D> context(new DeviceContext2D(module));
   if (!context->Init(size->width, size->height, is_always_opaque))
     return NULL;
-  context->AddRef();  // AddRef for the caller.
-  return context->GetResource();
+  return context->GetReference();
 }
 
 bool IsDeviceContext2D(PP_Resource resource) {
-  scoped_refptr<DeviceContext2D> context(
-      Resource::GetAs<DeviceContext2D>(resource));
-  return !!context.get();
+  return !!Resource::GetAs<DeviceContext2D>(resource);
 }
 
 bool Describe(PP_Resource device_context,
@@ -88,7 +85,7 @@ bool Describe(PP_Resource device_context,
               bool* is_always_opaque) {
   scoped_refptr<DeviceContext2D> context(
       Resource::GetAs<DeviceContext2D>(device_context));
-  if (!context.get())
+  if (!context)
     return false;
   return context->Describe(size, is_always_opaque);
 }
@@ -99,7 +96,7 @@ bool PaintImageData(PP_Resource device_context,
                     const PP_Rect* src_rect) {
   scoped_refptr<DeviceContext2D> context(
       Resource::GetAs<DeviceContext2D>(device_context));
-  if (!context.get())
+  if (!context)
     return false;
   return context->PaintImageData(image, top_left, src_rect);
 }
@@ -109,7 +106,7 @@ bool Scroll(PP_Resource device_context,
             const PP_Point* amount) {
   scoped_refptr<DeviceContext2D> context(
       Resource::GetAs<DeviceContext2D>(device_context));
-  if (!context.get())
+  if (!context)
     return false;
   return context->Scroll(clip_rect, amount);
 }
@@ -117,7 +114,7 @@ bool Scroll(PP_Resource device_context,
 bool ReplaceContents(PP_Resource device_context, PP_Resource image) {
   scoped_refptr<DeviceContext2D> context(
       Resource::GetAs<DeviceContext2D>(device_context));
-  if (!context.get())
+  if (!context)
     return false;
   return context->ReplaceContents(image);
 }
@@ -126,7 +123,7 @@ int32_t Flush(PP_Resource device_context,
               PP_CompletionCallback callback) {
   scoped_refptr<DeviceContext2D> context(
       Resource::GetAs<DeviceContext2D>(device_context));
-  if (!context.get())
+  if (!context)
     return PP_ERROR_BADRESOURCE;
   return context->Flush(callback);
 }
@@ -214,7 +211,7 @@ bool DeviceContext2D::PaintImageData(PP_Resource image,
     return false;
 
   scoped_refptr<ImageData> image_resource(Resource::GetAs<ImageData>(image));
-  if (!image_resource.get())
+  if (!image_resource)
     return false;
 
   QueuedOperation operation(QueuedOperation::PAINT);
@@ -269,7 +266,7 @@ bool DeviceContext2D::Scroll(const PP_Rect* clip_rect,
 
 bool DeviceContext2D::ReplaceContents(PP_Resource image) {
   scoped_refptr<ImageData> image_resource(Resource::GetAs<ImageData>(image));
-  if (!image_resource.get())
+  if (!image_resource)
     return false;
   if (image_resource->format() != PP_IMAGEDATAFORMAT_BGRA_PREMUL)
     return false;
@@ -301,7 +298,7 @@ int32_t DeviceContext2D::Flush(const PP_CompletionCallback& callback) {
     gfx::Rect op_rect;
     switch (operation.type) {
       case QueuedOperation::PAINT:
-        ExecutePaintImageData(operation.paint_image.get(),
+        ExecutePaintImageData(operation.paint_image,
                               operation.paint_x, operation.paint_y,
                               operation.paint_src_rect,
                               &op_rect);
@@ -312,7 +309,7 @@ int32_t DeviceContext2D::Flush(const PP_CompletionCallback& callback) {
                       &op_rect);
         break;
       case QueuedOperation::REPLACE:
-        ExecuteReplaceContents(operation.replace_image.get(), &op_rect);
+        ExecuteReplaceContents(operation.replace_image, &op_rect);
         break;
     }
     changed_rect = changed_rect.Union(op_rect);
@@ -343,7 +340,7 @@ bool DeviceContext2D::ReadImageData(PP_Resource image,
                                     const PP_Point* top_left) {
   // Get and validate the image object to paint into.
   scoped_refptr<ImageData> image_resource(Resource::GetAs<ImageData>(image));
-  if (!image_resource.get())
+  if (!image_resource)
     return false;
   if (image_resource->format() != PP_IMAGEDATAFORMAT_BGRA_PREMUL)
     return false;  // Must be in the right format.
@@ -360,7 +357,7 @@ bool DeviceContext2D::ReadImageData(PP_Resource image,
       image_data_->height())
     return false;
 
-  ImageDataAutoMapper auto_mapper(image_resource.get());
+  ImageDataAutoMapper auto_mapper(image_resource);
   if (!auto_mapper.is_valid())
     return false;
   skia::PlatformCanvas* dest_canvas = image_resource->mapped_canvas();
diff --git a/webkit/glue/plugins/pepper_directory_reader.cc b/webkit/glue/plugins/pepper_directory_reader.cc
index f575e2c..93f19eef 100644
--- a/webkit/glue/plugins/pepper_directory_reader.cc
+++ b/webkit/glue/plugins/pepper_directory_reader.cc
@@ -17,16 +17,15 @@ namespace {
 PP_Resource Create(PP_Resource directory_ref_id) {
   scoped_refptr<FileRef> directory_ref(
       Resource::GetAs<FileRef>(directory_ref_id));
-  if (!directory_ref.get())
+  if (!directory_ref)
     return 0;
 
   DirectoryReader* reader = new DirectoryReader(directory_ref);
-  reader->AddRef();  // AddRef for the caller;
-  return reader->GetResource();
+  return reader->GetReference();
 }
 
 bool IsDirectoryReader(PP_Resource resource) {
-  return !!Resource::GetAs<DirectoryReader>(resource).get();
+  return !!Resource::GetAs<DirectoryReader>(resource);
 }
 
 int32_t GetNextEntry(PP_Resource reader_id,
@@ -34,7 +33,7 @@ int32_t GetNextEntry(PP_Resource reader_id,
                      PP_CompletionCallback callback) {
   scoped_refptr<DirectoryReader> reader(
       Resource::GetAs<DirectoryReader>(reader_id));
-  if (!reader.get())
+  if (!reader)
     return PP_ERROR_BADRESOURCE;
 
   return reader->GetNextEntry(entry, callback);
diff --git a/webkit/glue/plugins/pepper_file_chooser.cc b/webkit/glue/plugins/pepper_file_chooser.cc
index 6c4c72a..5e45600 100644
--- a/webkit/glue/plugins/pepper_file_chooser.cc
+++ b/webkit/glue/plugins/pepper_file_chooser.cc
@@ -22,18 +22,17 @@ PP_Resource Create(PP_Instance instance_id,
     return 0;
 
   FileChooser* chooser = new FileChooser(instance, options);
-  chooser->AddRef();  // AddRef for the caller.
-  return chooser->GetResource();
+  return chooser->GetReference();
 }
 
 bool IsFileChooser(PP_Resource resource) {
-  return !!Resource::GetAs<FileChooser>(resource).get();
+  return !!Resource::GetAs<FileChooser>(resource);
 }
 
 int32_t Show(PP_Resource chooser_id, PP_CompletionCallback callback) {
   scoped_refptr<FileChooser> chooser(
-      Resource::GetAs<FileChooser>(chooser_id).get());
-  if (!chooser.get())
+      Resource::GetAs<FileChooser>(chooser_id));
+  if (!chooser)
     return PP_ERROR_BADRESOURCE;
 
   return chooser->Show(callback);
@@ -41,16 +40,15 @@ int32_t Show(PP_Resource chooser_id, PP_CompletionCallback callback) {
 
 PP_Resource GetNextChosenFile(PP_Resource chooser_id) {
   scoped_refptr<FileChooser> chooser(
-      Resource::GetAs<FileChooser>(chooser_id).get());
-  if (!chooser.get())
+      Resource::GetAs<FileChooser>(chooser_id));
+  if (!chooser)
     return 0;
 
   scoped_refptr<FileRef> file_ref(chooser->GetNextChosenFile());
-  if (!file_ref.get())
+  if (!file_ref)
     return 0;
-  file_ref->AddRef();  // AddRef for the caller.
 
-  return file_ref->GetResource();
+  return file_ref->GetReference();
 }
 
 const PPB_FileChooser ppb_filechooser = {
diff --git a/webkit/glue/plugins/pepper_file_io.cc b/webkit/glue/plugins/pepper_file_io.cc
index 7100c1f..46f7276 100644
--- a/webkit/glue/plugins/pepper_file_io.cc
+++ b/webkit/glue/plugins/pepper_file_io.cc
@@ -23,12 +23,11 @@ PP_Resource Create(PP_Module module_id) {
     return 0;
 
   FileIO* file_io = new FileIO(module);
-  file_io->AddRef();  // AddRef for the caller.
-  return file_io->GetResource();
+  return file_io->GetReference();
 }
 
 bool IsFileIO(PP_Resource resource) {
-  return !!Resource::GetAs<FileIO>(resource).get();
+  return !!Resource::GetAs<FileIO>(resource);
 }
 
 int32_t Open(PP_Resource file_io_id,
@@ -36,11 +35,11 @@ int32_t Open(PP_Resource file_io_id,
              int32_t open_flags,
              PP_CompletionCallback callback) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
-  if (!file_ref.get())
+  if (!file_ref)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->Open(file_ref, open_flags, callback);
@@ -50,7 +49,7 @@ int32_t Query(PP_Resource file_io_id,
               PP_FileInfo* info,
               PP_CompletionCallback callback) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->Query(info, callback);
@@ -61,7 +60,7 @@ int32_t Touch(PP_Resource file_io_id,
               PP_Time last_modified_time,
               PP_CompletionCallback callback) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->Touch(last_access_time, last_modified_time, callback);
@@ -73,7 +72,7 @@ int32_t Read(PP_Resource file_io_id,
              int32_t bytes_to_read,
              PP_CompletionCallback callback) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->Read(offset, buffer, bytes_to_read, callback);
@@ -85,7 +84,7 @@ int32_t Write(PP_Resource file_io_id,
               int32_t bytes_to_write,
               PP_CompletionCallback callback) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->Write(offset, buffer, bytes_to_write, callback);
@@ -95,7 +94,7 @@ int32_t SetLength(PP_Resource file_io_id,
                   int64_t length,
                   PP_CompletionCallback callback) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->SetLength(length, callback);
@@ -104,7 +103,7 @@ int32_t SetLength(PP_Resource file_io_id,
 int32_t Flush(PP_Resource file_io_id,
               PP_CompletionCallback callback) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->Flush(callback);
@@ -112,7 +111,7 @@ int32_t Flush(PP_Resource file_io_id,
 
 void Close(PP_Resource file_io_id) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return;
 
   file_io->Close();
@@ -133,7 +132,7 @@ const PPB_FileIO ppb_fileio = {
 
 int32_t GetOSFileDescriptor(PP_Resource file_io_id) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->GetOSFileDescriptor();
@@ -144,7 +143,7 @@ int32_t WillWrite(PP_Resource file_io_id,
                   int32_t bytes_to_write,
                   PP_CompletionCallback callback) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->WillWrite(offset, bytes_to_write, callback);
@@ -154,7 +153,7 @@ int32_t WillSetLength(PP_Resource file_io_id,
                       int64_t length,
                       PP_CompletionCallback callback) {
   scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
-  if (!file_io.get())
+  if (!file_io)
     return PP_ERROR_BADRESOURCE;
 
   return file_io->WillSetLength(length, callback);
diff --git a/webkit/glue/plugins/pepper_file_ref.cc b/webkit/glue/plugins/pepper_file_ref.cc
index 63563a1..9b42cff 100644
--- a/webkit/glue/plugins/pepper_file_ref.cc
+++ b/webkit/glue/plugins/pepper_file_ref.cc
@@ -50,8 +50,7 @@ PP_Resource CreateFileRef(PP_Instance instance_id,
                                   fs_type,
                                   validated_path,
                                   origin);
-  file_ref->AddRef();  // AddRef for the caller.
-  return file_ref->GetResource();
+  return file_ref->GetReference();
 }
 
 PP_Resource CreatePersistentFileRef(PP_Instance instance_id, const char* path) {
@@ -63,12 +62,12 @@ PP_Resource CreateTemporaryFileRef(PP_Instance instance_id, const char* path) {
 }
 
 bool IsFileRef(PP_Resource resource) {
-  return !!Resource::GetAs<FileRef>(resource).get();
+  return !!Resource::GetAs<FileRef>(resource);
 }
 
 PP_FileSystemType GetFileSystemType(PP_Resource file_ref_id) {
   scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
-  if (!file_ref.get())
+  if (!file_ref)
     return PP_FILESYSTEMTYPE_EXTERNAL;
 
   return file_ref->file_system_type();
@@ -76,7 +75,7 @@ PP_FileSystemType GetFileSystemType(PP_Resource file_ref_id) {
 
 PP_Var GetName(PP_Resource file_ref_id) {
   scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
-  if (!file_ref.get())
+  if (!file_ref)
     return PP_MakeVoid();
 
   return StringToPPVar(file_ref->GetName());
@@ -84,7 +83,7 @@ PP_Var GetName(PP_Resource file_ref_id) {
 
 PP_Var GetPath(PP_Resource file_ref_id) {
   scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
-  if (!file_ref.get())
+  if (!file_ref)
     return PP_MakeVoid();
 
   if (file_ref->file_system_type() == PP_FILESYSTEMTYPE_EXTERNAL)
@@ -95,18 +94,17 @@ PP_Var GetPath(PP_Resource file_ref_id) {
 
 PP_Resource GetParent(PP_Resource file_ref_id) {
   scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
-  if (!file_ref.get())
+  if (!file_ref)
     return 0;
 
   if (file_ref->file_system_type() == PP_FILESYSTEMTYPE_EXTERNAL)
     return 0;
 
   scoped_refptr<FileRef> parent_ref(file_ref->GetParent());
-  if (!parent_ref.get())
+  if (!parent_ref)
     return 0;
-  parent_ref->AddRef();  // AddRef for the caller.
 
-  return parent_ref->GetResource();
+  return parent_ref->GetReference();
 }
 
 const PPB_FileRef ppb_fileref = {
@@ -165,7 +163,6 @@ scoped_refptr<FileRef> FileRef::GetParent() {
   std::string parent_path = path_.substr(0, pos);
 
   FileRef* parent_ref = new FileRef(module(), fs_type_, parent_path, origin_);
-  parent_ref->AddRef();  // AddRef for the caller.
   return parent_ref;
 }
 
diff --git a/webkit/glue/plugins/pepper_font.cc b/webkit/glue/plugins/pepper_font.cc
index 8bc48a3..af4cb81d 100644
--- a/webkit/glue/plugins/pepper_font.cc
+++ b/webkit/glue/plugins/pepper_font.cc
@@ -34,9 +34,8 @@ PP_Resource MatchFontWithFallback(PP_Module module_id,
     return NULL;
 
   scoped_refptr<Font> font(new Font(module, fd));
-  font->AddRef();  // AddRef for the caller.
 
-  return font->GetResource();
+  return font->GetReference();
 #else
   // For trusted pepper plugins, this is only needed in Linux since font loading
   // on Windows and Mac works through the renderer sandbox.
@@ -45,7 +44,7 @@ PP_Resource MatchFontWithFallback(PP_Module module_id,
 }
 
 bool IsFont(PP_Resource resource) {
-  return !!Resource::GetAs<Font>(resource).get();
+  return !!Resource::GetAs<Font>(resource);
 }
 
 bool GetFontTable(PP_Resource font_id,
diff --git a/webkit/glue/plugins/pepper_image_data.cc b/webkit/glue/plugins/pepper_image_data.cc
index 51245b4..8288fe2 100644
--- a/webkit/glue/plugins/pepper_image_data.cc
+++ b/webkit/glue/plugins/pepper_image_data.cc
@@ -36,13 +36,12 @@ PP_Resource Create(PP_Module module_id,
   scoped_refptr<ImageData> data(new ImageData(module));
   if (!data->Init(format, size->width, size->height, init_to_zero))
     return NULL;
-  data->AddRef();  // AddRef for the caller.
 
-  return data->GetResource();
+  return data->GetReference();
 }
 
 bool IsImageData(PP_Resource resource) {
-  return !!Resource::GetAs<ImageData>(resource).get();
+  return !!Resource::GetAs<ImageData>(resource);
 }
 
 bool Describe(PP_Resource resource, PP_ImageDataDesc* desc) {
@@ -50,7 +49,7 @@ bool Describe(PP_Resource resource, PP_ImageDataDesc* desc) {
   memset(desc, 0, sizeof(PP_ImageDataDesc));
 
   scoped_refptr<ImageData> image_data(Resource::GetAs<ImageData>(resource));
-  if (!image_data.get())
+  if (!image_data)
     return false;
   image_data->Describe(desc);
   return true;
@@ -58,16 +57,15 @@ bool Describe(PP_Resource resource, PP_ImageDataDesc* desc) {
 
 void* Map(PP_Resource resource) {
   scoped_refptr<ImageData> image_data(Resource::GetAs<ImageData>(resource));
-  if (!image_data.get())
+  if (!image_data)
     return NULL;
   return image_data->Map();
 }
 
 void Unmap(PP_Resource resource) {
   scoped_refptr<ImageData> image_data(Resource::GetAs<ImageData>(resource));
-  if (!image_data)
-    return;
-  return image_data->Unmap();
+  if (image_data)
+    image_data->Unmap();
 }
 
 const PPB_ImageData ppb_imagedata = {
diff --git a/webkit/glue/plugins/pepper_plugin_instance.cc b/webkit/glue/plugins/pepper_plugin_instance.cc
index dcc7ea2..6a7bf54 100644
--- a/webkit/glue/plugins/pepper_plugin_instance.cc
+++ b/webkit/glue/plugins/pepper_plugin_instance.cc
@@ -376,8 +376,8 @@ bool PluginInstance::Initialize(WebPluginContainer* container,
 }
 
 bool PluginInstance::HandleDocumentLoad(URLLoader* loader) {
-  return instance_interface_->HandleDocumentLoad(GetPPInstance(),
-                                                 loader->GetResource());
+  Resource::ScopedResourceId resource(loader);
+  return instance_interface_->HandleDocumentLoad(GetPPInstance(), resource.id);
 }
 
 bool PluginInstance::HandleInputEvent(const WebKit::WebInputEvent& event,
diff --git a/webkit/glue/plugins/pepper_plugin_module.cc b/webkit/glue/plugins/pepper_plugin_module.cc
index e748e56..8ffd78b 100644
--- a/webkit/glue/plugins/pepper_plugin_module.cc
+++ b/webkit/glue/plugins/pepper_plugin_module.cc
@@ -75,21 +75,15 @@ base::MessageLoopProxy* GetMainThreadMessageLoop() {
 // PPB_Core --------------------------------------------------------------------
 
 void AddRefResource(PP_Resource resource) {
-  Resource* res = ResourceTracker::Get()->GetResource(resource);
-  if (!res) {
-    DLOG(WARNING) << "AddRef()ing a nonexistent resource";
-    return;
+  if (!ResourceTracker::Get()->AddRefResource(resource)) {
+    DLOG(WARNING) << "AddRefResource()ing a nonexistent resource";
   }
-  res->AddRef();
 }
 
 void ReleaseResource(PP_Resource resource) {
-  Resource* res = ResourceTracker::Get()->GetResource(resource);
-  if (!res) {
-    DLOG(WARNING) << "Release()ing a nonexistent resource";
-    return;
+  if (!ResourceTracker::Get()->UnrefResource(resource)) {
+    DLOG(WARNING) << "ReleaseResource()ing a nonexistent resource";
   }
-  res->Release();
 }
 
 void* MemAlloc(size_t num_bytes) {
diff --git a/webkit/glue/plugins/pepper_resource.cc b/webkit/glue/plugins/pepper_resource.cc
index fe2cf4b..c568183 100644
--- a/webkit/glue/plugins/pepper_resource.cc
+++ b/webkit/glue/plugins/pepper_resource.cc
@@ -4,21 +4,16 @@
 
 #include "webkit/glue/plugins/pepper_resource.h"
 
-#include "third_party/ppapi/c/pp_resource.h"
 #include "webkit/glue/plugins/pepper_resource_tracker.h"
 
 namespace pepper {
 
-Resource::Resource(PluginModule* module) : module_(module) {
-  ResourceTracker::Get()->AddResource(this);
+PP_Resource Resource::GetReference() {
+  ResourceTracker *tracker = ResourceTracker::Get();
+  if (resource_id_)
+    tracker->AddRefResource(resource_id_);
+  else
+    resource_id_ = tracker->AddResource(this);
+  return resource_id_;
 }
-
-Resource::~Resource() {
-  ResourceTracker::Get()->DeleteResource(this);
-}
-
-PP_Resource Resource::GetResource() const {
-  return reinterpret_cast<intptr_t>(this);
-}
-
 }  // namespace pepper
diff --git a/webkit/glue/plugins/pepper_resource.h b/webkit/glue/plugins/pepper_resource.h
index 4e347cb..417a06b 100644
--- a/webkit/glue/plugins/pepper_resource.h
+++ b/webkit/glue/plugins/pepper_resource.h
@@ -5,6 +5,7 @@
 #ifndef WEBKIT_GLUE_PLUGINS_PEPPER_RESOURCE_H_
 #define WEBKIT_GLUE_PLUGINS_PEPPER_RESOURCE_H_
 
+#include "base/logging.h"
 #include "base/basictypes.h"
 #include "base/ref_counted.h"
 #include "third_party/ppapi/c/pp_resource.h"
@@ -29,8 +30,8 @@ class Widget;
 
 class Resource : public base::RefCountedThreadSafe<Resource> {
  public:
-  explicit Resource(PluginModule* module);
-  virtual ~Resource();
+  explicit Resource(PluginModule* module)  : resource_id_(0), module_(module) {}
+  virtual ~Resource() {}
 
   // Returns NULL if the resource is invalid or is a different type.
   template<typename T>
@@ -39,8 +40,6 @@ class Resource : public base::RefCountedThreadSafe<Resource> {
     return resource ? resource->Cast<T>() : NULL;
   }
 
-  PP_Resource GetResource() const;
-
   PluginModule* module() const { return module_; }
 
   // Cast the resource into a specified type. This will return NULL if the
@@ -48,6 +47,27 @@ class Resource : public base::RefCountedThreadSafe<Resource> {
   // template call into As* functions.
   template <typename T> T* Cast() { return NULL; }
 
+  // Returns an resource id of this object. If the object doesn't have a
+  // resource id, new one is created with plugin refcount of 1. If it does,
+  // the refcount is incremented. Use this when you need to return a new
+  // reference to the plugin.
+  PP_Resource GetReference();
+
+  // When you need to ensure that a resource has a reference, but you do not
+  // want to increase the refcount (for example, if you need to call a plugin
+  // callback function with a reference), you can use this class. For example:
+  //
+  // plugin_callback(.., ScopedResourceId(resource).id, ...);
+  class ScopedResourceId {
+   public:
+    explicit ScopedResourceId(Resource* resource)
+        : id(resource->GetReference()) {}
+    ~ScopedResourceId() {
+      ResourceTracker::Get()->UnrefResource(id);
+    }
+    const PP_Resource id;
+  };
+
  private:
   // Type-specific getters for individual resource types. These will return
   // NULL if the resource does not match the specified type. Used by the Cast()
@@ -66,7 +86,25 @@ class Resource : public base::RefCountedThreadSafe<Resource> {
   virtual URLResponseInfo* AsURLResponseInfo() { return NULL; }
   virtual Widget* AsWidget() { return NULL; }
 
-  PluginModule* module_;  // Non-owning pointer to our module.
+ private:
+  // If referenced by a plugin, holds the id of this resource object. Do not
+  // access this member directly, because it is possible that the plugin holds
+  // no references to the object, and therefore the resource_id_ is zero. Use
+  // either GetReference() to obtain a new resource_id and increase the
+  // refcount, or TemporaryReference when you do not want to increase the
+  // refcount.
+  PP_Resource resource_id_;
+
+  // Non-owning pointer to our module.
+  PluginModule* module_;
+
+  // Called by the resource tracker when the last plugin reference has been
+  // dropped.
+  friend class ResourceTracker;
+  void StoppedTracking() {
+    DCHECK(resource_id_ != 0);
+    resource_id_ = 0;
+  }
 
   DISALLOW_COPY_AND_ASSIGN(Resource);
 };
diff --git a/webkit/glue/plugins/pepper_resource_tracker.cc b/webkit/glue/plugins/pepper_resource_tracker.cc
index c8779e4..8aa94d2 100644
--- a/webkit/glue/plugins/pepper_resource_tracker.cc
+++ b/webkit/glue/plugins/pepper_resource_tracker.cc
@@ -4,57 +4,58 @@
 
 #include "webkit/glue/plugins/pepper_resource_tracker.h"
 
+#include <limits>
 #include <set>
 
 #include "base/logging.h"
 #include "third_party/ppapi/c/pp_resource.h"
-#include "webkit/glue/plugins/pepper_buffer.h"
-#include "webkit/glue/plugins/pepper_device_context_2d.h"
-#include "webkit/glue/plugins/pepper_directory_reader.h"
-#include "webkit/glue/plugins/pepper_file_chooser.h"
-#include "webkit/glue/plugins/pepper_file_io.h"
-#include "webkit/glue/plugins/pepper_file_ref.h"
-#include "webkit/glue/plugins/pepper_image_data.h"
 #include "webkit/glue/plugins/pepper_resource.h"
-#include "webkit/glue/plugins/pepper_url_loader.h"
-#include "webkit/glue/plugins/pepper_url_request_info.h"
-#include "webkit/glue/plugins/pepper_url_response_info.h"
 
 namespace pepper {
 
-ResourceTracker::ResourceTracker() {
-}
-
-ResourceTracker::~ResourceTracker() {
-}
-
-// static
-ResourceTracker* ResourceTracker::Get() {
-  return Singleton<ResourceTracker>::get();
-}
-
 scoped_refptr<Resource> ResourceTracker::GetResource(PP_Resource res) const {
-  AutoLock lock(lock_);
-  Resource* resource = reinterpret_cast<Resource*>(res);
-  if (live_resources_.find(resource) == live_resources_.end())
+  ResourceMap::const_iterator result = live_resources_.find(res);
+  if (result == live_resources_.end()) {
     return scoped_refptr<Resource>();
-  return scoped_refptr<Resource>(resource);
+  }
+  return result->second.first;
 }
 
-void ResourceTracker::AddResource(Resource* resource) {
-  AutoLock lock(lock_);
-  DCHECK(live_resources_.find(resource) == live_resources_.end());
-  live_resources_.insert(resource);
+PP_Resource ResourceTracker::AddResource(Resource* resource) {
+  // If the plugin manages to create 4B resources...
+  if (last_id_ == std::numeric_limits<PP_Resource>::max()) {
+    return 0;
+  }
+  // Add the resource with plugin use-count 1.
+  ++last_id_;
+  live_resources_.insert(std::make_pair(last_id_, std::make_pair(resource, 1)));
+  return last_id_;
+}
+
+bool ResourceTracker::AddRefResource(PP_Resource res) {
+  ResourceMap::iterator i = live_resources_.find(res);
+  if (i != live_resources_.end()) {
+    // We don't protect against overflow, since a plugin as malicious as to ref
+    // once per every byte in the address space could have just as well unrefed
+    // one time too many.
+    ++i->second.second;
+    return true;
+  } else {
+    return false;
+  }
 }
 
-void ResourceTracker::DeleteResource(Resource* resource) {
-  AutoLock lock(lock_);
-  ResourceSet::iterator found = live_resources_.find(resource);
-  if (found == live_resources_.end()) {
-    NOTREACHED();
-    return;
+bool ResourceTracker::UnrefResource(PP_Resource res) {
+  ResourceMap::iterator i = live_resources_.find(res);
+  if (i != live_resources_.end()) {
+    if (!--i->second.second) {
+      i->second.first->StoppedTracking();
+      live_resources_.erase(i);
+    }
+    return true;
+  } else {
+    return false;
   }
-  live_resources_.erase(found);
 }
 
 }  // namespace pepper
diff --git a/webkit/glue/plugins/pepper_resource_tracker.h b/webkit/glue/plugins/pepper_resource_tracker.h
index 35c382d..d06c9ba 100644
--- a/webkit/glue/plugins/pepper_resource_tracker.h
+++ b/webkit/glue/plugins/pepper_resource_tracker.h
@@ -9,7 +9,7 @@
 
 #include "base/atomic_sequence_num.h"
 #include "base/basictypes.h"
-#include "base/lock.h"
+#include "base/hash_tables.h"
 #include "base/ref_counted.h"
 #include "base/singleton.h"
 #include "third_party/ppapi/c/pp_resource.h"
@@ -25,7 +25,9 @@ class Resource;
 class ResourceTracker {
  public:
   // Returns the pointer to the singleton object.
-  static ResourceTracker* Get();
+  static ResourceTracker* Get() {
+    return Singleton<ResourceTracker>::get();
+  }
 
   // The returned pointer will be NULL if there is no resource. Note that this
   // return value is a scoped_refptr so that we ensure the resource is valid
@@ -34,23 +36,36 @@ class ResourceTracker {
   // the object will get deleted out from under us.
   scoped_refptr<Resource> GetResource(PP_Resource res) const;
 
-  // Adds the given resource to the tracker and assigns it a resource ID. The
-  // assigned resource ID will be returned.
-  void AddResource(Resource* resource);
-
-  void DeleteResource(Resource* resource);
+  // Increment resource's plugin refcount. See ResourceAndRefCount comments
+  // below.
+  bool AddRefResource(PP_Resource res);
+  bool UnrefResource(PP_Resource res);
 
  private:
   friend struct DefaultSingletonTraits<ResourceTracker>;
-
-  ResourceTracker();
-  ~ResourceTracker();
-
-  // Hold this lock when accessing this object's members.
-  mutable Lock lock_;
-
-  typedef std::set<Resource*> ResourceSet;
-  ResourceSet live_resources_;
+  friend class Resource;
+
+  // Prohibit creation other then by the Singleton class.
+  ResourceTracker() : last_id_(0) {}
+  ~ResourceTracker() {}
+
+  // Adds the given resource to the tracker and assigns it a resource ID and
+  // refcount of 1. The assigned resource ID will be returned. Used only by the
+  // Resource class.
+  PP_Resource AddResource(Resource* resource);
+
+  // Last assigned resource ID.
+  PP_Resource last_id_;
+
+  // For each PP_Resource, keep the Resource* (as refptr) and plugin use count.
+  // This use count is different then Resource's RefCount, and is manipulated
+  // using this RefResource/UnrefResource. When it drops to zero, we just remove
+  // the resource from this resource tracker, but the resource object will be
+  // alive so long as some scoped_refptr still holds it's reference. This
+  // prevents plugins from forcing destruction of Resource objects.
+  typedef std::pair<scoped_refptr<Resource>, size_t> ResourceAndRefCount;
+  typedef base::hash_map<PP_Resource, ResourceAndRefCount> ResourceMap;
+  ResourceMap live_resources_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceTracker);
 };
diff --git a/webkit/glue/plugins/pepper_scrollbar.cc b/webkit/glue/plugins/pepper_scrollbar.cc
index 155bd64..48db8d4 100644
--- a/webkit/glue/plugins/pepper_scrollbar.cc
+++ b/webkit/glue/plugins/pepper_scrollbar.cc
@@ -31,13 +31,11 @@ PP_Resource Create(PP_Instance instance_id, bool vertical) {
     return NULL;
 
   scoped_refptr<Scrollbar> scrollbar(new Scrollbar(instance, vertical));
-  scrollbar->AddRef();  // AddRef for the caller.
-
-  return scrollbar->GetResource();
+  return scrollbar->GetReference();
 }
 
 bool IsScrollbar(PP_Resource resource) {
-  return !!Resource::GetAs<Scrollbar>(resource).get();
+  return !!Resource::GetAs<Scrollbar>(resource);
 }
 
 uint32_t GetThickness() {
@@ -46,20 +44,20 @@ uint32_t GetThickness() {
 
 uint32_t GetValue(PP_Resource resource) {
   scoped_refptr<Scrollbar> scrollbar(Resource::GetAs<Scrollbar>(resource));
-  if (!scrollbar.get())
+  if (!scrollbar)
     return 0;
   return scrollbar->GetValue();
 }
 
 void SetValue(PP_Resource resource, uint32_t value) {
   scoped_refptr<Scrollbar> scrollbar(Resource::GetAs<Scrollbar>(resource));
-  if (scrollbar.get())
+  if (scrollbar)
     scrollbar->SetValue(value);
 }
 
 void SetDocumentSize(PP_Resource resource, uint32_t size) {
   scoped_refptr<Scrollbar> scrollbar(Resource::GetAs<Scrollbar>(resource));
-  if (scrollbar.get())
+  if (scrollbar)
     scrollbar->SetDocumentSize(size);
 }
 
@@ -67,7 +65,7 @@ void SetTickMarks(PP_Resource resource,
                   const PP_Rect* tick_marks,
                   uint32_t count) {
   scoped_refptr<Scrollbar> scrollbar(Resource::GetAs<Scrollbar>(resource));
-  if (scrollbar.get())
+  if (scrollbar)
     scrollbar->SetTickMarks(tick_marks, count);
 }
 
@@ -75,7 +73,7 @@ void ScrollBy(PP_Resource resource,
               PP_ScrollBy unit,
               int32_t multiplier) {
   scoped_refptr<Scrollbar> scrollbar(Resource::GetAs<Scrollbar>(resource));
-  if (scrollbar.get())
+  if (scrollbar)
     scrollbar->ScrollBy(unit, multiplier);
 }
 
@@ -184,8 +182,9 @@ void Scrollbar::valueChanged(WebKit::WebScrollbar* scrollbar) {
       module()->GetPluginInterface(PPP_SCROLLBAR_INTERFACE));
   if (!ppp_scrollbar)
     return;
+  ScopedResourceId resource(this);
   ppp_scrollbar->ValueChanged(
-      instance()->GetPPInstance(), GetResource(), scrollbar_->value());
+      instance()->GetPPInstance(), resource.id, scrollbar_->value());
 }
 
 void Scrollbar::invalidateScrollbarRect(WebKit::WebScrollbar* scrollbar,
diff --git a/webkit/glue/plugins/pepper_url_loader.cc b/webkit/glue/plugins/pepper_url_loader.cc
index 617cbc2..aa09686 100644
--- a/webkit/glue/plugins/pepper_url_loader.cc
+++ b/webkit/glue/plugins/pepper_url_loader.cc
@@ -42,25 +42,24 @@ PP_Resource Create(PP_Instance instance_id) {
     return 0;
 
   URLLoader* loader = new URLLoader(instance);
-  loader->AddRef();  // AddRef for the caller.
 
-  return loader->GetResource();
+  return loader->GetReference();
 }
 
 bool IsURLLoader(PP_Resource resource) {
-  return !!Resource::GetAs<URLLoader>(resource).get();
+  return !!Resource::GetAs<URLLoader>(resource);
 }
 
 int32_t Open(PP_Resource loader_id,
              PP_Resource request_id,
              PP_CompletionCallback callback) {
   scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
-  if (!loader.get())
+  if (!loader)
     return PP_ERROR_BADRESOURCE;
 
   scoped_refptr<URLRequestInfo> request(
       Resource::GetAs<URLRequestInfo>(request_id));
-  if (!request.get())
+  if (!request)
     return PP_ERROR_BADRESOURCE;
 
   return loader->Open(request, callback);
@@ -69,7 +68,7 @@ int32_t Open(PP_Resource loader_id,
 int32_t FollowRedirect(PP_Resource loader_id,
                        PP_CompletionCallback callback) {
   scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
-  if (!loader.get())
+  if (!loader)
     return PP_ERROR_BADRESOURCE;
 
   return loader->FollowRedirect(callback);
@@ -79,7 +78,7 @@ bool GetUploadProgress(PP_Resource loader_id,
                        int64_t* bytes_sent,
                        int64_t* total_bytes_to_be_sent) {
   scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
-  if (!loader.get())
+  if (!loader)
     return false;
 
   *bytes_sent = loader->bytes_sent();
@@ -91,7 +90,7 @@ bool GetDownloadProgress(PP_Resource loader_id,
                          int64_t* bytes_received,
                          int64_t* total_bytes_to_be_received) {
   scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
-  if (!loader.get())
+  if (!loader)
     return false;
 
   *bytes_received = loader->bytes_received();
@@ -101,15 +100,14 @@ bool GetDownloadProgress(PP_Resource loader_id,
 
 PP_Resource GetResponseInfo(PP_Resource loader_id) {
   scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
-  if (!loader.get())
+  if (!loader)
     return 0;
 
   URLResponseInfo* response_info = loader->response_info();
   if (!response_info)
     return 0;
-  response_info->AddRef();  // AddRef for the caller.
 
-  return response_info->GetResource();
+  return response_info->GetReference();
 }
 
 int32_t ReadResponseBody(PP_Resource loader_id,
@@ -117,7 +115,7 @@ int32_t ReadResponseBody(PP_Resource loader_id,
                          int32_t bytes_to_read,
                          PP_CompletionCallback callback) {
   scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
-  if (!loader.get())
+  if (!loader)
     return PP_ERROR_BADRESOURCE;
 
   return loader->ReadResponseBody(buffer, bytes_to_read, callback);
@@ -125,7 +123,7 @@ int32_t ReadResponseBody(PP_Resource loader_id,
 
 void Close(PP_Resource loader_id) {
   scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
-  if (!loader.get())
+  if (!loader)
     return;
 
   loader->Close();
diff --git a/webkit/glue/plugins/pepper_url_request_info.cc b/webkit/glue/plugins/pepper_url_request_info.cc
index 9ce79ce..d230f20 100644
--- a/webkit/glue/plugins/pepper_url_request_info.cc
+++ b/webkit/glue/plugins/pepper_url_request_info.cc
@@ -53,13 +53,12 @@ PP_Resource Create(PP_Module module_id) {
     return 0;
 
   URLRequestInfo* request = new URLRequestInfo(module);
-  request->AddRef();  // AddRef for the caller.
 
-  return request->GetResource();
+  return request->GetReference();
 }
 
 bool IsURLRequestInfo(PP_Resource resource) {
-  return !!Resource::GetAs<URLRequestInfo>(resource).get();
+  return !!Resource::GetAs<URLRequestInfo>(resource);
 }
 
 bool SetProperty(PP_Resource request_id,
@@ -67,7 +66,7 @@ bool SetProperty(PP_Resource request_id,
                  PP_Var var) {
   scoped_refptr<URLRequestInfo> request(
       Resource::GetAs<URLRequestInfo>(request_id));
-  if (!request.get())
+  if (!request)
     return false;
 
   if (var.type == PP_VARTYPE_BOOL)
@@ -82,7 +81,7 @@ bool SetProperty(PP_Resource request_id,
 bool AppendDataToBody(PP_Resource request_id, PP_Var var) {
   scoped_refptr<URLRequestInfo> request(
       Resource::GetAs<URLRequestInfo>(request_id));
-  if (!request.get())
+  if (!request)
     return false;
 
   String* data = GetString(var);
@@ -99,11 +98,11 @@ bool AppendFileToBody(PP_Resource request_id,
                       PP_Time expected_last_modified_time) {
   scoped_refptr<URLRequestInfo> request(
       Resource::GetAs<URLRequestInfo>(request_id));
-  if (!request.get())
+  if (!request)
     return false;
 
   scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
-  if (!file_ref.get())
+  if (!file_ref)
     return false;
 
   return request->AppendFileToBody(file_ref,
diff --git a/webkit/glue/plugins/pepper_url_response_info.cc b/webkit/glue/plugins/pepper_url_response_info.cc
index b5db4bc5..bff92aa 100644
--- a/webkit/glue/plugins/pepper_url_response_info.cc
+++ b/webkit/glue/plugins/pepper_url_response_info.cc
@@ -38,14 +38,14 @@ class HeaderFlattener : public WebHTTPHeaderVisitor {
 };
 
 bool IsURLResponseInfo(PP_Resource resource) {
-  return !!Resource::GetAs<URLResponseInfo>(resource).get();
+  return !!Resource::GetAs<URLResponseInfo>(resource);
 }
 
 PP_Var GetProperty(PP_Resource response_id,
                    PP_URLResponseProperty property) {
   scoped_refptr<URLResponseInfo> response(
       Resource::GetAs<URLResponseInfo>(response_id));
-  if (!response.get())
+  if (!response)
     return PP_MakeVoid();
 
   return response->GetProperty(property);
@@ -62,7 +62,7 @@ PP_Resource GetBody(PP_Resource response_id) {
     return 0;
   body->AddRef();  // AddRef for the caller.
 
-  return body->GetResource();
+  return body->GetReference();
 }
 
 const PPB_URLResponseInfo ppb_urlresponseinfo = {
diff --git a/webkit/glue/plugins/pepper_widget.cc b/webkit/glue/plugins/pepper_widget.cc
index 9d345274..74b0e40 100644
--- a/webkit/glue/plugins/pepper_widget.cc
+++ b/webkit/glue/plugins/pepper_widget.cc
@@ -18,31 +18,31 @@ namespace pepper {
 namespace {
 
 bool IsWidget(PP_Resource resource) {
-  return !!Resource::GetAs<Widget>(resource).get();
+  return !!Resource::GetAs<Widget>(resource);
 }
 
 bool Paint(PP_Resource resource, const PP_Rect* rect, PP_Resource image_id) {
   scoped_refptr<Widget> widget(Resource::GetAs<Widget>(resource));
-  if (!widget.get())
+  if (!widget)
     return false;
 
   scoped_refptr<ImageData> image(Resource::GetAs<ImageData>(image_id));
-  return widget.get() && widget->Paint(rect, image);
+  return widget && widget->Paint(rect, image);
 }
 
 bool HandleEvent(PP_Resource resource, const PP_Event* event) {
   scoped_refptr<Widget> widget(Resource::GetAs<Widget>(resource));
-  return widget.get() && widget->HandleEvent(event);
+  return widget && widget->HandleEvent(event);
 }
 
 bool GetLocation(PP_Resource resource, PP_Rect* location) {
   scoped_refptr<Widget> widget(Resource::GetAs<Widget>(resource));
-  return widget.get() && widget->GetLocation(location);
+  return widget && widget->GetLocation(location);
 }
 
 void SetLocation(PP_Resource resource, const PP_Rect* location) {
   scoped_refptr<Widget> widget(Resource::GetAs<Widget>(resource));
-  if (widget.get())
+  if (widget)
     widget->SetLocation(location);
 }
 
@@ -84,7 +84,8 @@ void Widget::Invalidate(const PP_Rect* dirty) {
       module()->GetPluginInterface(PPP_WIDGET_INTERFACE));
   if (!widget)
     return;
-  widget->Invalidate(instance_->GetPPInstance(), GetResource(), dirty);
+  ScopedResourceId resource(this);
+  widget->Invalidate(instance_->GetPPInstance(), resource.id, dirty);
 }
 
 }  // namespace pepper