Check for some extensions before calling potentially NULL GL entry points.

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc

 // Copyright (c) 2016 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_passthrough.h"
 
+#include "base/strings/string_split.h"
 #include "gpu/command_buffer/service/feature_info.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "ui/gl/gl_version_info.h"
 
 namespace gpu {
 namespace gles2 {
 
 namespace {
 template <typename ClientType, typename ServiceType, typename DeleteFunction>
 void DeleteServiceObjects(ClientServiceMap<ClientType, ServiceType>* id_map,
@@ skipping 147 matching lines @@
   surface_ = surface;
   offscreen_ = offscreen;
 
   if (!group_->Initialize(this, attrib_helper.context_type,
                           disallowed_features)) {
     group_ = NULL;  // Must not destroy ContextGroup if it is not initialized.
     Destroy(true);
     return false;
   }
 
+  InitializeNativeCaps();
+
   // Check for required extensions
   if (!feature_info_->feature_flags().angle_robust_client_memory ||
-      !feature_info_->feature_flags().chromium_bind_generates_resource) {
+      !feature_info_->feature_flags().chromium_bind_generates_resource ||
+      !has_chromium_copy_texture_ || !has_chromium_copy_compressed_texture_) {
     // TODO(geofflang): Verify that ANGLE_webgl_compatibility is enabled if this
     // is a WebGL context (depends on crbug.com/671217).
     Destroy(true);
     return false;
   }
 
   image_manager_.reset(new ImageManager());
 
   bind_generates_resource_ = group_->bind_generates_resource();
 
@@ skipping 653 matching lines @@
       glBindTexture(target, service_id);
     }
   }
 
   // Reset the active texture unit if it was changed
   if (cur_texture_unit != active_texture_unit_) {
     glActiveTexture(static_cast<GLenum>(GL_TEXTURE0 + active_texture_unit_));
   }
 }
 
+void GLES2DecoderPassthroughImpl::InitializeNativeCaps() {
+  has_es3_ = feature_info_->gl_version_info().IsAtLeastGLES(3, 0);
+
+  std::vector<std::string> extension_tokens =
+      base::SplitString(gl::GetGLExtensionsFromCurrentContext(), " ",
+                        base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+  std::unordered_set<std::string> extension_set(extension_tokens.begin(),
+                                                extension_tokens.end());
+
+  has_ext_discard_framebuffer_ =
+      extension_set.count("GL_EXT_discard_framebuffer") > 0;
+  has_angle_framebuffer_multisample_ =
+      extension_set.count("GL_ANGLE_framebuffer_multisample") > 0;
+  has_chromium_copy_texture_ =
+      extension_set.count("GL_CHROMIUM_copy_texture") > 0;
+  has_chromium_copy_compressed_texture_ =
+      extension_set.count("GL_CHROMIUM_copy_compressed_texture") > 0;
+}
+
 #define GLES2_CMD_OP(name)                                               \
   {                                                                      \
       &GLES2DecoderPassthroughImpl::Handle##name, cmds::name::kArgFlags, \
       cmds::name::cmd_flags,                                             \
       sizeof(cmds::name) / sizeof(CommandBufferEntry) - 1,               \
   }, /* NOLINT */
 
 const GLES2DecoderPassthroughImpl::CommandInfo
     GLES2DecoderPassthroughImpl::command_info[] = {
         GLES2_COMMAND_LIST(GLES2_CMD_OP)};
 
 #undef GLES2_CMD_OP
 
 }  // namespace gles2
 }  // namespace gpu