Cache GL's viewport on the GPU command buffer client side.

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 3534 matching lines @@
                 &caps.max_fragment_uniform_vectors, 1);
   DoGetIntegerv(GL_MAX_RENDERBUFFER_SIZE, &caps.max_renderbuffer_size, 1);
   DoGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &caps.max_texture_image_units, 1);
   DoGetIntegerv(GL_MAX_TEXTURE_SIZE, &caps.max_texture_size, 1);
   DoGetIntegerv(GL_MAX_VARYING_VECTORS, &caps.max_varying_vectors, 1);
   DoGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &caps.max_vertex_attribs, 1);
   DoGetIntegerv(GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS,
                 &caps.max_vertex_texture_image_units, 1);
   DoGetIntegerv(GL_MAX_VERTEX_UNIFORM_VECTORS, &caps.max_vertex_uniform_vectors,
                 1);
+  {
+    GLint dims[2] = {0, 0};
+    DoGetIntegerv(GL_MAX_VIEWPORT_DIMS, dims, 2);
+    caps.max_viewport_width = dims[0];
+    caps.max_viewport_height = dims[1];
+  }
   DoGetIntegerv(GL_NUM_COMPRESSED_TEXTURE_FORMATS,
                 &caps.num_compressed_texture_formats, 1);
   DoGetIntegerv(GL_NUM_SHADER_BINARY_FORMATS, &caps.num_shader_binary_formats,
                 1);
   DoGetIntegerv(GL_BIND_GENERATES_RESOURCE_CHROMIUM,
                 &caps.bind_generates_resource_chromium, 1);
   if (feature_info_->IsWebGL2OrES3Context()) {
     // TODO(zmo): Note that some parameter values could be more than 32-bit,
     // but for now we clamp them to 32-bit max.
     DoGetIntegerv(GL_MAX_3D_TEXTURE_SIZE, &caps.max_3d_texture_size, 1);
@@ skipping 15369 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