Exposed support for dynamically enabling extensions in command buffer...

gpu/command_buffer/service/feature_info.h

 // Copyright (c) 2010 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.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_FEATURE_INFO_H_
 #define GPU_COMMAND_BUFFER_SERVICE_FEATURE_INFO_H_
 
 #include <string>
+#include <vector>
 #include "gpu/command_buffer/service/gles2_cmd_validation.h"
 
 namespace gpu {
 namespace gles2 {
 
 // FeatureInfo records the features that are available for a particular context.
 class FeatureInfo {
  public:
   struct FeatureFlags {
     FeatureFlags()
@@ skipping 28 matching lines @@
   }
 
   const std::string& extensions() const {
     return extensions_;
   }
 
   const FeatureFlags& feature_flags() const {
     return feature_flags_;
   }
 
+  // Returns a string containing the extensions that can be
+  // successfully requested on the current hardware.
+  const std::string& RequestableExtensions();
+
  private:
+  // Checks the given extension or extensions for availability. If it
+  // is available, then if it is desired, should_enable is set to
+  // true. (No other changes are made in this case.) Otherwise,
+  // "extension" (and not alternate_extension) is added to the set of
+  // requestable extensions.
+  void DoSimpleTestForEnablingExtension(

[greggman, 2010/12/04 01:28:44]

Why do these take void extension_helper? Why not ExtensionHelper*?

+      void* extensions_helper, const char* extension, bool* should_enable);
+  void DoSimpleTestForEnablingExtension(
+      void* extensions_helper, const char* extension,
+      const char* alternate_extension, bool* should_enable);
+
   void AddExtensionString(const std::string& str);
+  void AddRequestableExtensionString(const std::string& str);
+  void RemoveRequestableExtensionString(const std::string& str);
 
   Validators validators_;
 
   // The extensions string returned by glGetString(GL_EXTENSIONS);
   std::string extensions_;
 
+  // The list of extensions returned by glGetRequestableExtensionsCHROMIUM().
+  std::vector<std::string> requestable_extensions_list_;

[greggman, 2010/12/04 01:28:44]

why a list and not a set? This would simplify the code where you add and remove
them

+  bool requestable_extensions_dirty_;
+  std::string requestable_extensions_;
+
   // Flags for some features
   FeatureFlags feature_flags_;
 
   DISALLOW_COPY_AND_ASSIGN(FeatureInfo);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_FEATURE_INFO_H_