gpu: Clarify sized texture format is available only if ES3 context or immutable texture is supported

gpu/command_buffer/service/texture_manager.h

 // Copyright (c) 2012 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_TEXTURE_MANAGER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_TEXTURE_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 482 matching lines @@
                                  GLenum target,
                                  GLint level_diff,
                                  GLenum internal_format,
                                  GLsizei width,
                                  GLsizei height,
                                  GLsizei depth,
                                  GLenum format,
                                  GLenum type);
 
   static bool ColorRenderable(const FeatureInfo* feature_info,
-                              GLenum internal_format);
+                              GLenum internal_format,
+                              bool immutable);
 
   static bool TextureFilterable(const FeatureInfo* feature_info,
                                 GLenum internal_format,
-                                GLenum type);
+                                GLenum type,
+                                bool immutable);
 
   // Sets the Texture's target
   // Parameters:
   //   target: GL_TEXTURE_2D or GL_TEXTURE_CUBE_MAP or
   //           GL_TEXTURE_EXTERNAL_OES or GL_TEXTURE_RECTANGLE_ARB
   //           GL_TEXTURE_2D_ARRAY or GL_TEXTURE_3D (for GLES3)
   //   max_levels: The maximum levels this type of target can have.
   void SetTarget(GLenum target, GLint max_levels);
 
   // Update info about this texture.
@@ skipping 736 matching lines @@
  private:
   DecoderTextureState* texture_state_;
   base::TimeTicks begin_time_;
   DISALLOW_COPY_AND_ASSIGN(ScopedTextureUploadTimer);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_TEXTURE_MANAGER_H_