Hook ANGLE_request_extension up to the passthrough cmd decoder.

gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
index def9b0f8a28f5b3d94a59b0ddb16c4ed95ffbe95..ae441dbd0d3f2300531479625c60bd83567f1b9d 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
@@ -2596,14 +2596,26 @@ error::Error GLES2DecoderPassthroughImpl::DoResizeCHROMIUM(GLuint width,
 
 error::Error GLES2DecoderPassthroughImpl::DoGetRequestableExtensionsCHROMIUM(
     const char** extensions) {
-  *extensions = "";
-  NOTIMPLEMENTED();
+  *extensions = reinterpret_cast<const char*>(
+      glGetString(GL_REQUESTABLE_EXTENSIONS_ANGLE));
   return error::kNoError;
 }
 
 error::Error GLES2DecoderPassthroughImpl::DoRequestExtensionCHROMIUM(
     const char* extension) {
-  NOTIMPLEMENTED();
+  glRequestExtensionANGLE(extension);
+
+  // Make sure there are no pending GL errors before re-initializing feature
+  // info
+  FlushErrors();
+
+  // Make sure newly enabled extensions are exposed and usable.
+  context_->ReinitializeDynamicBindings();
+  if (!feature_info_->Initialize(feature_info_->context_type(),
+                                 feature_info_->disallowed_features())) {
+    return error::kLostContext;
+  }
+
   return error::kNoError;
 }