Fix PRIMITIVE_RESTART_FIXED_INDEX handling in command buffer and WebGL 2.0.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index ac7209792314dad5e0dbf7002e85e9847d9e71ca..73b81668aa398adb8e314a740e1a38d6a499be55 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -8283,7 +8283,9 @@ error::Error GLES2DecoderImpl::DoDrawElements(const char* function_name,
       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;
@@ -8380,8 +8382,18 @@ GLuint GLES2DecoderImpl::DoGetMaxValueInBufferCHROMIUM(
     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,