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

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
index 742793d0a190fa8aa0db443b4d0e99801b0abbba..62046b11c52639c414398943ab70fba076d63314 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc
@@ -4,6 +4,7 @@
 
 #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"
@@ -171,9 +172,12 @@ bool GLES2DecoderPassthroughImpl::Initialize(
     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);
@@ -847,6 +851,25 @@ void GLES2DecoderPassthroughImpl::UpdateTextureBinding(GLenum target,
   }
 }
 
+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, \