Fix PRIMITIVE_RESTART_FIXED_INDEX handling in command buffer and WebGL 2.0.

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // 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.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ skipping 8265 matching lines @@
 
   if (count == 0 || primcount == 0) {
     return error::kNoError;
   }
 
   GLuint max_vertex_accessed;
   Buffer* element_array_buffer =
       state_.vertex_attrib_manager->element_array_buffer();
 
   if (!element_array_buffer->GetMaxValueForRange(
-      offset, count, type, &max_vertex_accessed)) {
+          offset, count, type,
+          state_.enable_flags.primitive_restart_fixed_index,
+          &max_vertex_accessed)) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION, function_name, "range out of bounds for buffer");
     return error::kNoError;
   }
 
   if (IsDrawValid(function_name, max_vertex_accessed, instanced, primcount)) {
     if (!ClearUnclearedTextures()) {
       LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, function_name, "out of memory");
       return error::kNoError;
     }
@@ skipping 76 matching lines @@
 
 GLuint GLES2DecoderImpl::DoGetMaxValueInBufferCHROMIUM(
     GLuint buffer_id, GLsizei count, GLenum type, GLuint offset) {
   GLuint max_vertex_accessed = 0;
   Buffer* buffer = GetBuffer(buffer_id);
   if (!buffer) {
     // TODO(gman): Should this be a GL error or a command buffer error?
     LOCAL_SET_GL_ERROR(
         GL_INVALID_VALUE, "GetMaxValueInBufferCHROMIUM", "unknown buffer");
   } else {
+    // The max value is used here to emulate client-side vertex
+    // arrays, by uploading enough vertices into buffer objects to
+    // cover the DrawElements call. Baking the primitive restart bit
+    // into this result isn't strictly correct in all cases; the
+    // client side code should pass down the bit and decide how to use
+    // the result. However, the only caller makes the draw call
+    // immediately afterward, so the state won't change between this
+    // query and the draw call.
     if (!buffer->GetMaxValueForRange(
-        offset, count, type, &max_vertex_accessed)) {
+            offset, count, type,
+            state_.enable_flags.primitive_restart_fixed_index,
+            &max_vertex_accessed)) {
       // TODO(gman): Should this be a GL error or a command buffer error?
       LOCAL_SET_GL_ERROR(
           GL_INVALID_OPERATION,
           "GetMaxValueInBufferCHROMIUM", "range out of bounds for buffer");
     }
   }
   return max_vertex_accessed;
 }
 
 void GLES2DecoderImpl::DoShaderSource(
@@ skipping 7853 matching lines @@
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "base/macros.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu