Add a GetAs<ResourceType> template.

Move all the dependencies of new PP_Resource types into plugin_resource.h.
BUG=none
TEST=none

Review URL: http://codereview.chromium.org/2800028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@51056 0039d316-1c4b-4281-b951-d872f2087c98

15 files changed, 93 insertions, 146 deletions

diff --git a/webkit/glue/plugins/pepper_buffer.cc b/webkit/glue/plugins/pepper_buffer.cc
index f8d1384..4d94975 100644
--- a/webkit/glue/plugins/pepper_buffer.cc
+++ b/webkit/glue/plugins/pepper_buffer.cc
@@ -14,7 +14,6 @@
 #include "third_party/ppapi/c/ppb_buffer.h"
 #include "webkit/glue/plugins/pepper_plugin_instance.h"
 #include "webkit/glue/plugins/pepper_plugin_module.h"
-#include "webkit/glue/plugins/pepper_resource_tracker.h"
 
 namespace pepper {
 
@@ -34,12 +33,11 @@ PP_Resource Create(PP_Module module_id, int32_t size) {
 }
 
 bool IsBuffer(PP_Resource resource) {
-  return !!ResourceTracker::Get()->GetAsBuffer(resource).get();
+  return !!Resource::GetAs<Buffer>(resource).get();
 }
 
 bool Describe(PP_Resource resource, int32_t* size_in_bytes) {
-  scoped_refptr<Buffer> buffer(
-      ResourceTracker::Get()->GetAsBuffer(resource));
+  scoped_refptr<Buffer> buffer(Resource::GetAs<Buffer>(resource));
   if (!buffer.get())
     return false;
   buffer->Describe(size_in_bytes);
@@ -47,16 +45,14 @@ bool Describe(PP_Resource resource, int32_t* size_in_bytes) {
 }
 
 void* Map(PP_Resource resource) {
-  scoped_refptr<Buffer> buffer(
-      ResourceTracker::Get()->GetAsBuffer(resource));
+  scoped_refptr<Buffer> buffer(Resource::GetAs<Buffer>(resource));
   if (!buffer.get())
     return NULL;
   return buffer->Map();
 }
 
 void Unmap(PP_Resource resource) {
-  scoped_refptr<Buffer> buffer(
-      ResourceTracker::Get()->GetAsBuffer(resource));
+  scoped_refptr<Buffer> buffer(Resource::GetAs<Buffer>(resource));
   if (!buffer)
     return;
   return buffer->Unmap();
diff --git a/webkit/glue/plugins/pepper_device_context_2d.cc b/webkit/glue/plugins/pepper_device_context_2d.cc
index 3d81fcb..4dcfa5e 100644
--- a/webkit/glue/plugins/pepper_device_context_2d.cc
+++ b/webkit/glue/plugins/pepper_device_context_2d.cc
@@ -21,7 +21,6 @@
 #include "webkit/glue/plugins/pepper_image_data.h"
 #include "webkit/glue/plugins/pepper_plugin_instance.h"
 #include "webkit/glue/plugins/pepper_plugin_module.h"
-#include "webkit/glue/plugins/pepper_resource_tracker.h"
 
 #if defined(OS_MACOSX)
 #include "base/mac_util.h"
@@ -78,14 +77,14 @@ PP_Resource Create(PP_Module module_id, int32_t width, int32_t height,
 
 bool IsDeviceContext2D(PP_Resource resource) {
   scoped_refptr<DeviceContext2D> context(
-      ResourceTracker::Get()->GetAsDeviceContext2D(resource));
+      Resource::GetAs<DeviceContext2D>(resource));
   return !!context.get();
 }
 
 bool Describe(PP_Resource device_context,
               int32_t* width, int32_t* height, bool* is_always_opaque) {
   scoped_refptr<DeviceContext2D> context(
-      ResourceTracker::Get()->GetAsDeviceContext2D(device_context));
+      Resource::GetAs<DeviceContext2D>(device_context));
   if (!context.get())
     return false;
   return context->Describe(width, height, is_always_opaque);
@@ -96,7 +95,7 @@ bool PaintImageData(PP_Resource device_context,
                     int32_t x, int32_t y,
                     const PP_Rect* src_rect) {
   scoped_refptr<DeviceContext2D> context(
-      ResourceTracker::Get()->GetAsDeviceContext2D(device_context));
+      Resource::GetAs<DeviceContext2D>(device_context));
   if (!context.get())
     return false;
   return context->PaintImageData(image, x, y, src_rect);
@@ -106,7 +105,7 @@ bool Scroll(PP_Resource device_context,
             const PP_Rect* clip_rect,
             int32_t dx, int32_t dy) {
   scoped_refptr<DeviceContext2D> context(
-      ResourceTracker::Get()->GetAsDeviceContext2D(device_context));
+      Resource::GetAs<DeviceContext2D>(device_context));
   if (!context.get())
     return false;
   return context->Scroll(clip_rect, dx, dy);
@@ -114,7 +113,7 @@ bool Scroll(PP_Resource device_context,
 
 bool ReplaceContents(PP_Resource device_context, PP_Resource image) {
   scoped_refptr<DeviceContext2D> context(
-      ResourceTracker::Get()->GetAsDeviceContext2D(device_context));
+      Resource::GetAs<DeviceContext2D>(device_context));
   if (!context.get())
     return false;
   return context->ReplaceContents(image);
@@ -123,7 +122,7 @@ bool ReplaceContents(PP_Resource device_context, PP_Resource image) {
 int32_t Flush(PP_Resource device_context,
               PP_CompletionCallback callback) {
   scoped_refptr<DeviceContext2D> context(
-      ResourceTracker::Get()->GetAsDeviceContext2D(device_context));
+      Resource::GetAs<DeviceContext2D>(device_context));
   if (!context.get())
     return PP_Error_BadResource;
   return context->Flush(callback);
@@ -209,8 +208,7 @@ bool DeviceContext2D::Describe(int32_t* width, int32_t* height,
 bool DeviceContext2D::PaintImageData(PP_Resource image,
                                      int32_t x, int32_t y,
                                      const PP_Rect* src_rect) {
-  scoped_refptr<ImageData> image_resource(
-      ResourceTracker::Get()->GetAsImageData(image));
+  scoped_refptr<ImageData> image_resource(Resource::GetAs<ImageData>(image));
   if (!image_resource.get())
     return false;
 
@@ -262,8 +260,7 @@ bool DeviceContext2D::Scroll(const PP_Rect* clip_rect,
 }
 
 bool DeviceContext2D::ReplaceContents(PP_Resource image) {
-  scoped_refptr<ImageData> image_resource(
-      ResourceTracker::Get()->GetAsImageData(image));
+  scoped_refptr<ImageData> image_resource(Resource::GetAs<ImageData>(image));
   if (!image_resource.get())
     return false;
   if (image_resource->format() != PP_IMAGEDATAFORMAT_BGRA_PREMUL)
@@ -336,8 +333,7 @@ int32_t DeviceContext2D::Flush(const PP_CompletionCallback& callback) {
 
 bool DeviceContext2D::ReadImageData(PP_Resource image, int32_t x, int32_t y) {
   // Get and validate the image object to paint into.
-  scoped_refptr<ImageData> image_resource(
-      ResourceTracker::Get()->GetAsImageData(image));
+  scoped_refptr<ImageData> image_resource(Resource::GetAs<ImageData>(image));
   if (!image_resource.get())
     return false;
   if (image_resource->format() != PP_IMAGEDATAFORMAT_BGRA_PREMUL)
diff --git a/webkit/glue/plugins/pepper_directory_reader.cc b/webkit/glue/plugins/pepper_directory_reader.cc
index 3abaa40..429fb24 100644
--- a/webkit/glue/plugins/pepper_directory_reader.cc
+++ b/webkit/glue/plugins/pepper_directory_reader.cc
@@ -16,7 +16,7 @@ namespace {
 
 PP_Resource Create(PP_Resource directory_ref_id) {
   scoped_refptr<FileRef> directory_ref(
-      ResourceTracker::Get()->GetAsFileRef(directory_ref_id));
+      Resource::GetAs<FileRef>(directory_ref_id));
   if (!directory_ref.get())
     return 0;
 
@@ -26,14 +26,14 @@ PP_Resource Create(PP_Resource directory_ref_id) {
 }
 
 bool IsDirectoryReader(PP_Resource resource) {
-  return !!ResourceTracker::Get()->GetAsDirectoryReader(resource).get();
+  return !!Resource::GetAs<DirectoryReader>(resource).get();
 }
 
 int32_t GetNextEntry(PP_Resource reader_id,
                      PP_DirectoryEntry* entry,
                      PP_CompletionCallback callback) {
   scoped_refptr<DirectoryReader> reader(
-      ResourceTracker::Get()->GetAsDirectoryReader(reader_id));
+      Resource::GetAs<DirectoryReader>(reader_id));
   if (!reader.get())
     return PP_Error_BadResource;
 
diff --git a/webkit/glue/plugins/pepper_file_chooser.cc b/webkit/glue/plugins/pepper_file_chooser.cc
index 8a5e2b0..a2e96b2 100644
--- a/webkit/glue/plugins/pepper_file_chooser.cc
+++ b/webkit/glue/plugins/pepper_file_chooser.cc
@@ -27,12 +27,12 @@ PP_Resource Create(PP_Instance instance_id,
 }
 
 bool IsFileChooser(PP_Resource resource) {
-  return !!ResourceTracker::Get()->GetAsFileChooser(resource).get();
+  return !!Resource::GetAs<FileChooser>(resource).get();
 }
 
 int32_t Show(PP_Resource chooser_id, PP_CompletionCallback callback) {
   scoped_refptr<FileChooser> chooser(
-      ResourceTracker::Get()->GetAsFileChooser(chooser_id).get());
+      Resource::GetAs<FileChooser>(chooser_id).get());
   if (!chooser.get())
     return PP_Error_BadResource;
 
@@ -41,7 +41,7 @@ int32_t Show(PP_Resource chooser_id, PP_CompletionCallback callback) {
 
 PP_Resource GetNextChosenFile(PP_Resource chooser_id) {
   scoped_refptr<FileChooser> chooser(
-      ResourceTracker::Get()->GetAsFileChooser(chooser_id).get());
+      Resource::GetAs<FileChooser>(chooser_id).get());
   if (!chooser.get())
     return 0;
 
diff --git a/webkit/glue/plugins/pepper_file_io.cc b/webkit/glue/plugins/pepper_file_io.cc
index 72ffc12..926a6db 100644
--- a/webkit/glue/plugins/pepper_file_io.cc
+++ b/webkit/glue/plugins/pepper_file_io.cc
@@ -28,20 +28,18 @@ PP_Resource Create(PP_Module module_id) {
 }
 
 bool IsFileIO(PP_Resource resource) {
-  return !!ResourceTracker::Get()->GetAsFileIO(resource).get();
+  return !!Resource::GetAs<FileIO>(resource).get();
 }
 
 int32_t Open(PP_Resource file_io_id,
              PP_Resource file_ref_id,
              int32_t open_flags,
              PP_CompletionCallback callback) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
-  scoped_refptr<FileRef> file_ref(
-      ResourceTracker::Get()->GetAsFileRef(file_ref_id));
+  scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
   if (!file_ref.get())
     return PP_Error_BadResource;
 
@@ -51,8 +49,7 @@ int32_t Open(PP_Resource file_io_id,
 int32_t Query(PP_Resource file_io_id,
               PP_FileInfo* info,
               PP_CompletionCallback callback) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
@@ -63,8 +60,7 @@ int32_t Touch(PP_Resource file_io_id,
               PP_Time last_access_time,
               PP_Time last_modified_time,
               PP_CompletionCallback callback) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
@@ -76,8 +72,7 @@ int32_t Read(PP_Resource file_io_id,
              char* buffer,
              int32_t bytes_to_read,
              PP_CompletionCallback callback) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
@@ -89,8 +84,7 @@ int32_t Write(PP_Resource file_io_id,
               const char* buffer,
               int32_t bytes_to_write,
               PP_CompletionCallback callback) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
@@ -100,8 +94,7 @@ int32_t Write(PP_Resource file_io_id,
 int32_t SetLength(PP_Resource file_io_id,
                   int64_t length,
                   PP_CompletionCallback callback) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
@@ -110,8 +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(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
@@ -119,8 +111,7 @@ int32_t Flush(PP_Resource file_io_id,
 }
 
 void Close(PP_Resource file_io_id) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return;
 
@@ -141,8 +132,7 @@ const PPB_FileIO ppb_fileio = {
 };
 
 int32_t GetOSFileDescriptor(PP_Resource file_io_id) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
@@ -153,8 +143,7 @@ int32_t WillWrite(PP_Resource file_io_id,
                   int64_t offset,
                   int32_t bytes_to_write,
                   PP_CompletionCallback callback) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
@@ -164,8 +153,7 @@ int32_t WillWrite(PP_Resource file_io_id,
 int32_t WillSetLength(PP_Resource file_io_id,
                       int64_t length,
                       PP_CompletionCallback callback) {
-  scoped_refptr<FileIO> file_io(
-      ResourceTracker::Get()->GetAsFileIO(file_io_id));
+  scoped_refptr<FileIO> file_io(Resource::GetAs<FileIO>(file_io_id));
   if (!file_io.get())
     return PP_Error_BadResource;
 
diff --git a/webkit/glue/plugins/pepper_file_ref.cc b/webkit/glue/plugins/pepper_file_ref.cc
index e014ff6..45ec567 100644
--- a/webkit/glue/plugins/pepper_file_ref.cc
+++ b/webkit/glue/plugins/pepper_file_ref.cc
@@ -63,12 +63,11 @@ PP_Resource CreateTemporaryFileRef(PP_Instance instance_id, const char* path) {
 }
 
 bool IsFileRef(PP_Resource resource) {
-  return !!ResourceTracker::Get()->GetAsFileRef(resource).get();
+  return !!Resource::GetAs<FileRef>(resource).get();
 }
 
 PP_FileSystemType GetFileSystemType(PP_Resource file_ref_id) {
-  scoped_refptr<FileRef> file_ref(
-      ResourceTracker::Get()->GetAsFileRef(file_ref_id));
+  scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
   if (!file_ref.get())
     return PP_FileSystemType_External;
 
@@ -76,8 +75,7 @@ PP_FileSystemType GetFileSystemType(PP_Resource file_ref_id) {
 }
 
 PP_Var GetName(PP_Resource file_ref_id) {
-  scoped_refptr<FileRef> file_ref(
-      ResourceTracker::Get()->GetAsFileRef(file_ref_id));
+  scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
   if (!file_ref.get())
     return PP_MakeVoid();
 
@@ -85,8 +83,7 @@ PP_Var GetName(PP_Resource file_ref_id) {
 }
 
 PP_Var GetPath(PP_Resource file_ref_id) {
-  scoped_refptr<FileRef> file_ref(
-      ResourceTracker::Get()->GetAsFileRef(file_ref_id));
+  scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
   if (!file_ref.get())
     return PP_MakeVoid();
 
@@ -97,8 +94,7 @@ PP_Var GetPath(PP_Resource file_ref_id) {
 }
 
 PP_Resource GetParent(PP_Resource file_ref_id) {
-  scoped_refptr<FileRef> file_ref(
-      ResourceTracker::Get()->GetAsFileRef(file_ref_id));
+  scoped_refptr<FileRef> file_ref(Resource::GetAs<FileRef>(file_ref_id));
   if (!file_ref.get())
     return 0;
 
diff --git a/webkit/glue/plugins/pepper_image_data.cc b/webkit/glue/plugins/pepper_image_data.cc
index 783f0a1..56cf877e 100644
--- a/webkit/glue/plugins/pepper_image_data.cc
+++ b/webkit/glue/plugins/pepper_image_data.cc
@@ -16,7 +16,6 @@
 #include "third_party/ppapi/c/ppb_image_data.h"
 #include "webkit/glue/plugins/pepper_plugin_instance.h"
 #include "webkit/glue/plugins/pepper_plugin_module.h"
-#include "webkit/glue/plugins/pepper_resource_tracker.h"
 
 namespace pepper {
 
@@ -43,7 +42,7 @@ PP_Resource Create(PP_Module module_id,
 }
 
 bool IsImageData(PP_Resource resource) {
-  return !!ResourceTracker::Get()->GetAsImageData(resource).get();
+  return !!Resource::GetAs<ImageData>(resource).get();
 }
 
 bool Describe(PP_Resource resource,
@@ -51,8 +50,7 @@ bool Describe(PP_Resource resource,
   // Give predictable values on failure.
   memset(desc, 0, sizeof(PP_ImageDataDesc));
 
-  scoped_refptr<ImageData> image_data(
-      ResourceTracker::Get()->GetAsImageData(resource));
+  scoped_refptr<ImageData> image_data(Resource::GetAs<ImageData>(resource));
   if (!image_data.get())
     return false;
   image_data->Describe(desc);
@@ -60,16 +58,14 @@ bool Describe(PP_Resource resource,
 }
 
 void* Map(PP_Resource resource) {
-  scoped_refptr<ImageData> image_data(
-      ResourceTracker::Get()->GetAsImageData(resource));
+  scoped_refptr<ImageData> image_data(Resource::GetAs<ImageData>(resource));
   if (!image_data.get())
     return NULL;
   return image_data->Map();
 }
 
 void Unmap(PP_Resource resource) {
-  scoped_refptr<ImageData> image_data(
-      ResourceTracker::Get()->GetAsImageData(resource));
+  scoped_refptr<ImageData> image_data(Resource::GetAs<ImageData>(resource));
   if (!image_data)
     return;
   return image_data->Unmap();
diff --git a/webkit/glue/plugins/pepper_plugin_instance.cc b/webkit/glue/plugins/pepper_plugin_instance.cc
index d86fffc..97ec093 100644
--- a/webkit/glue/plugins/pepper_plugin_instance.cc
+++ b/webkit/glue/plugins/pepper_plugin_instance.cc
@@ -23,7 +23,6 @@
 #include "webkit/glue/plugins/pepper_device_context_2d.h"
 #include "webkit/glue/plugins/pepper_plugin_delegate.h"
 #include "webkit/glue/plugins/pepper_plugin_module.h"
-#include "webkit/glue/plugins/pepper_resource_tracker.h"
 #include "webkit/glue/plugins/pepper_var.h"
 
 using WebKit::WebFrame;
@@ -214,12 +213,9 @@ bool PluginInstance::BindGraphicsDeviceContext(PP_Resource device_id) {
     return true;
   }
 
-  scoped_refptr<Resource> device_resource =
-      ResourceTracker::Get()->GetResource(device_id);
-  if (!device_resource.get())
-    return false;
+  scoped_refptr<DeviceContext2D> device_2d =
+      Resource::GetAs<DeviceContext2D>(device_id);
 
-  DeviceContext2D* device_2d = device_resource->AsDeviceContext2D();
   if (device_2d) {
     if (!device_2d->BindToInstance(this))
       return false;  // Can't bind to more than one instance.
diff --git a/webkit/glue/plugins/pepper_plugin_module.cc b/webkit/glue/plugins/pepper_plugin_module.cc
index 4bb5ea11..4752156 100644
--- a/webkit/glue/plugins/pepper_plugin_module.cc
+++ b/webkit/glue/plugins/pepper_plugin_module.cc
@@ -117,7 +117,7 @@ bool ReadImageData(PP_Resource device_context_2d,
                    PP_Resource image,
                    int32_t x, int32_t y) {
   scoped_refptr<DeviceContext2D> context(
-      ResourceTracker::Get()->GetAsDeviceContext2D(device_context_2d));
+      Resource::GetAs<DeviceContext2D>(device_context_2d));
   if (!context.get())
     return false;
   return context->ReadImageData(image, x, y);
diff --git a/webkit/glue/plugins/pepper_resource.h b/webkit/glue/plugins/pepper_resource.h
index efcc211..fdb9d01 100644
--- a/webkit/glue/plugins/pepper_resource.h
+++ b/webkit/glue/plugins/pepper_resource.h
@@ -8,6 +8,7 @@
 #include "base/basictypes.h"
 #include "base/ref_counted.h"
 #include "third_party/ppapi/c/pp_resource.h"
+#include "webkit/glue/plugins/pepper_resource_tracker.h"
 
 namespace pepper {
 
@@ -28,12 +29,26 @@ class Resource : public base::RefCountedThreadSafe<Resource> {
   explicit Resource(PluginModule* module);
   virtual ~Resource();
 
+  // Returns NULL if the resource is invalid or is a different type.
+  template<typename T>
+  static scoped_refptr<T> GetAs(PP_Resource res) {
+    scoped_refptr<Resource> resource = ResourceTracker::Get()->GetResource(res);
+    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
+  // resource does not match the specified type. Specializations of this
+  // template call into As* functions.
+  template <typename T> T* Cast() { return NULL; }
+
+ private:
   // Type-specific getters for individual resource types. These will return
-  // NULL if the resource does not match the specified type.
+  // NULL if the resource does not match the specified type. Used by the Cast()
+  // function.
   virtual Buffer* AsBuffer() { return NULL; }
   virtual DeviceContext2D* AsDeviceContext2D() { return NULL; }
   virtual DirectoryReader* AsDirectoryReader() { return NULL; }
@@ -45,12 +60,29 @@ class Resource : public base::RefCountedThreadSafe<Resource> {
   virtual URLRequestInfo* AsURLRequestInfo() { return NULL; }
   virtual URLResponseInfo* AsURLResponseInfo() { return NULL; }
 
- private:
   PluginModule* module_;  // Non-owning pointer to our module.
 
   DISALLOW_COPY_AND_ASSIGN(Resource);
 };
 
+// Cast() specializations.
+#define DEFINE_RESOURCE_CAST(Type)                   \
+  template <> inline Type* Resource::Cast<Type>() {  \
+      return As##Type();                             \
+  }
+
+DEFINE_RESOURCE_CAST(Buffer)
+DEFINE_RESOURCE_CAST(DeviceContext2D)
+DEFINE_RESOURCE_CAST(DirectoryReader)
+DEFINE_RESOURCE_CAST(FileChooser)
+DEFINE_RESOURCE_CAST(FileIO)
+DEFINE_RESOURCE_CAST(FileRef)
+DEFINE_RESOURCE_CAST(ImageData)
+DEFINE_RESOURCE_CAST(URLLoader)
+DEFINE_RESOURCE_CAST(URLRequestInfo)
+DEFINE_RESOURCE_CAST(URLResponseInfo)
+
+#undef DEFINE_RESOURCE_CAST
 }  // namespace pepper
 
 #endif  // WEBKIT_GLUE_PLUGINS_PEPPER_RESOURCE_H_
diff --git a/webkit/glue/plugins/pepper_resource_tracker.cc b/webkit/glue/plugins/pepper_resource_tracker.cc
index 077c95b..c8779e4 100644
--- a/webkit/glue/plugins/pepper_resource_tracker.cc
+++ b/webkit/glue/plugins/pepper_resource_tracker.cc
@@ -57,24 +57,4 @@ void ResourceTracker::DeleteResource(Resource* resource) {
   live_resources_.erase(found);
 }
 
-#define GET_AS_TYPE_IMPL(Type)                            \
-  scoped_refptr<Type> ResourceTracker::GetAs##Type(       \
-      PP_Resource res) const {                            \
-    scoped_refptr<Resource> resource = GetResource(res);  \
-    if (!resource.get())                                  \
-      return scoped_refptr<Type>();                       \
-    return scoped_refptr<Type>(resource->As##Type());     \
-  }
-
-GET_AS_TYPE_IMPL(Buffer)
-GET_AS_TYPE_IMPL(DeviceContext2D)
-GET_AS_TYPE_IMPL(DirectoryReader)
-GET_AS_TYPE_IMPL(FileChooser)
-GET_AS_TYPE_IMPL(FileIO)
-GET_AS_TYPE_IMPL(FileRef)
-GET_AS_TYPE_IMPL(ImageData)
-GET_AS_TYPE_IMPL(URLLoader)
-GET_AS_TYPE_IMPL(URLRequestInfo)
-GET_AS_TYPE_IMPL(URLResponseInfo)
-
 }  // namespace pepper
diff --git a/webkit/glue/plugins/pepper_resource_tracker.h b/webkit/glue/plugins/pepper_resource_tracker.h
index cfe2e68..35c382d 100644
--- a/webkit/glue/plugins/pepper_resource_tracker.h
+++ b/webkit/glue/plugins/pepper_resource_tracker.h
@@ -16,17 +16,7 @@
 
 namespace pepper {
 
-class Buffer;
-class DeviceContext2D;
-class DirectoryReader;
-class FileChooser;
-class FileIO;
-class FileRef;
-class ImageData;
 class Resource;
-class URLLoader;
-class URLRequestInfo;
-class URLResponseInfo;
 
 // This class maintains a global list of all live pepper resources. It allows
 // us to check resource ID validity and to map them to a specific module.
@@ -39,7 +29,7 @@ class ResourceTracker {
 
   // 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
-  // from the point of the loopkup to the point that the calling code needs it.
+  // from the point of the lookup to the point that the calling code needs it.
   // Otherwise, the plugin could Release() the resource on another thread and
   // the object will get deleted out from under us.
   scoped_refptr<Resource> GetResource(PP_Resource res) const;
@@ -50,19 +40,6 @@ class ResourceTracker {
 
   void DeleteResource(Resource* resource);
 
-  // Helpers for converting resources to a specific type. Returns NULL if the
-  // resource is invalid or is a different type.
-  scoped_refptr<Buffer> GetAsBuffer(PP_Resource res) const;
-  scoped_refptr<DeviceContext2D> GetAsDeviceContext2D(PP_Resource res) const;
-  scoped_refptr<DirectoryReader> GetAsDirectoryReader(PP_Resource res) const;
-  scoped_refptr<FileChooser> GetAsFileChooser(PP_Resource res) const;
-  scoped_refptr<FileIO> GetAsFileIO(PP_Resource res) const;
-  scoped_refptr<FileRef> GetAsFileRef(PP_Resource res) const;
-  scoped_refptr<ImageData> GetAsImageData(PP_Resource res) const;
-  scoped_refptr<URLLoader> GetAsURLLoader(PP_Resource res) const;
-  scoped_refptr<URLRequestInfo> GetAsURLRequestInfo(PP_Resource res) const;
-  scoped_refptr<URLResponseInfo> GetAsURLResponseInfo(PP_Resource res) const;
-
  private:
   friend struct DefaultSingletonTraits<ResourceTracker>;
 
diff --git a/webkit/glue/plugins/pepper_url_loader.cc b/webkit/glue/plugins/pepper_url_loader.cc
index 26be21d..4c38ef4 100644
--- a/webkit/glue/plugins/pepper_url_loader.cc
+++ b/webkit/glue/plugins/pepper_url_loader.cc
@@ -9,7 +9,6 @@
 #include "third_party/ppapi/c/pp_errors.h"
 #include "third_party/ppapi/c/ppb_url_loader.h"
 #include "webkit/glue/plugins/pepper_plugin_instance.h"
-#include "webkit/glue/plugins/pepper_resource_tracker.h"
 #include "webkit/glue/plugins/pepper_url_request_info.h"
 #include "webkit/glue/plugins/pepper_url_response_info.h"
 
@@ -29,19 +28,18 @@ PP_Resource Create(PP_Instance instance_id) {
 }
 
 bool IsURLLoader(PP_Resource resource) {
-  return !!ResourceTracker::Get()->GetAsURLLoader(resource).get();
+  return !!Resource::GetAs<URLLoader>(resource).get();
 }
 
 int32_t Open(PP_Resource loader_id,
              PP_Resource request_id,
              PP_CompletionCallback callback) {
-  scoped_refptr<URLLoader> loader(
-      ResourceTracker::Get()->GetAsURLLoader(loader_id));
+  scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
   if (!loader.get())
     return PP_Error_BadResource;
 
   scoped_refptr<URLRequestInfo> request(
-      ResourceTracker::Get()->GetAsURLRequestInfo(request_id));
+      Resource::GetAs<URLRequestInfo>(request_id));
   if (!request.get())
     return PP_Error_BadResource;
 
@@ -50,8 +48,7 @@ int32_t Open(PP_Resource loader_id,
 
 int32_t FollowRedirect(PP_Resource loader_id,
                        PP_CompletionCallback callback) {
-  scoped_refptr<URLLoader> loader(
-      ResourceTracker::Get()->GetAsURLLoader(loader_id));
+  scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
   if (!loader.get())
     return PP_Error_BadResource;
 
@@ -61,8 +58,7 @@ int32_t FollowRedirect(PP_Resource loader_id,
 bool GetUploadProgress(PP_Resource loader_id,
                        int64_t* bytes_sent,
                        int64_t* total_bytes_to_be_sent) {
-  scoped_refptr<URLLoader> loader(
-      ResourceTracker::Get()->GetAsURLLoader(loader_id));
+  scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
   if (!loader.get())
     return false;
 
@@ -74,8 +70,7 @@ bool GetUploadProgress(PP_Resource loader_id,
 bool GetDownloadProgress(PP_Resource loader_id,
                          int64_t* bytes_received,
                          int64_t* total_bytes_to_be_received) {
-  scoped_refptr<URLLoader> loader(
-      ResourceTracker::Get()->GetAsURLLoader(loader_id));
+  scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
   if (!loader.get())
     return false;
 
@@ -85,8 +80,7 @@ bool GetDownloadProgress(PP_Resource loader_id,
 }
 
 PP_Resource GetResponseInfo(PP_Resource loader_id) {
-  scoped_refptr<URLLoader> loader(
-      ResourceTracker::Get()->GetAsURLLoader(loader_id));
+  scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
   if (!loader.get())
     return 0;
 
@@ -102,8 +96,7 @@ int32_t ReadResponseBody(PP_Resource loader_id,
                          char* buffer,
                          int32_t bytes_to_read,
                          PP_CompletionCallback callback) {
-  scoped_refptr<URLLoader> loader(
-      ResourceTracker::Get()->GetAsURLLoader(loader_id));
+  scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
   if (!loader.get())
     return PP_Error_BadResource;
 
@@ -111,8 +104,7 @@ int32_t ReadResponseBody(PP_Resource loader_id,
 }
 
 void Close(PP_Resource loader_id) {
-  scoped_refptr<URLLoader> loader(
-      ResourceTracker::Get()->GetAsURLLoader(loader_id));
+  scoped_refptr<URLLoader> loader(Resource::GetAs<URLLoader>(loader_id));
   if (!loader.get())
     return;
 
diff --git a/webkit/glue/plugins/pepper_url_request_info.cc b/webkit/glue/plugins/pepper_url_request_info.cc
index 9eef1f9..0f48a7b 100644
--- a/webkit/glue/plugins/pepper_url_request_info.cc
+++ b/webkit/glue/plugins/pepper_url_request_info.cc
@@ -7,7 +7,6 @@
 #include "base/logging.h"
 #include "third_party/ppapi/c/pp_var.h"
 #include "webkit/glue/plugins/pepper_plugin_module.h"
-#include "webkit/glue/plugins/pepper_resource_tracker.h"
 #include "webkit/glue/plugins/pepper_string.h"
 #include "webkit/glue/plugins/pepper_var.h"
 
@@ -27,14 +26,14 @@ PP_Resource Create(PP_Module module_id) {
 }
 
 bool IsURLRequestInfo(PP_Resource resource) {
-  return !!ResourceTracker::Get()->GetAsURLRequestInfo(resource).get();
+  return !!Resource::GetAs<URLRequestInfo>(resource).get();
 }
 
 bool SetProperty(PP_Resource request_id,
                  PP_URLRequestProperty property,
                  PP_Var var) {
   scoped_refptr<URLRequestInfo> request(
-      ResourceTracker::Get()->GetAsURLRequestInfo(request_id));
+      Resource::GetAs<URLRequestInfo>(request_id));
   if (!request.get())
     return false;
 
@@ -49,7 +48,7 @@ bool SetProperty(PP_Resource request_id,
 
 bool AppendDataToBody(PP_Resource request_id, PP_Var var) {
   scoped_refptr<URLRequestInfo> request(
-      ResourceTracker::Get()->GetAsURLRequestInfo(request_id));
+      Resource::GetAs<URLRequestInfo>(request_id));
   if (!request.get())
     return false;
 
diff --git a/webkit/glue/plugins/pepper_url_response_info.cc b/webkit/glue/plugins/pepper_url_response_info.cc
index 506eb47..ed92c6c 100644
--- a/webkit/glue/plugins/pepper_url_response_info.cc
+++ b/webkit/glue/plugins/pepper_url_response_info.cc
@@ -6,20 +6,19 @@
 
 #include "base/logging.h"
 #include "third_party/ppapi/c/pp_var.h"
-#include "webkit/glue/plugins/pepper_resource_tracker.h"
 
 namespace pepper {
 
 namespace {
 
 bool IsURLResponseInfo(PP_Resource resource) {
-  return !!ResourceTracker::Get()->GetAsURLResponseInfo(resource).get();
+  return !!Resource::GetAs<URLResponseInfo>(resource).get();
 }
 
 PP_Var GetProperty(PP_Resource response_id,
                    PP_URLResponseProperty property) {
   scoped_refptr<URLResponseInfo> response(
-      ResourceTracker::Get()->GetAsURLResponseInfo(response_id));
+      Resource::GetAs<URLResponseInfo>(response_id));
   if (!response.get())
     return PP_MakeVoid();