Fix blits from multisampled renderbuffers to alpha:false WebGL back buffer.

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 9bfcb6b2750c7578ba5e0b76107cdb2812d64803..3600f809af1e651a59682c19bd055293b4d035ff 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc
@@ -3485,22 +3485,15 @@ error::Error GLES2DecoderPassthroughImpl::DoBindUniformLocationCHROMIUM(
 error::Error GLES2DecoderPassthroughImpl::DoBindTexImage2DCHROMIUM(
     GLenum target,
     GLint imageId) {
-  if (target != GL_TEXTURE_2D) {
-    InsertError(GL_INVALID_ENUM, "Invalid target");
-    return error::kNoError;
-  }
-
-  gl::GLImage* image = image_manager_->LookupImage(imageId);
-  if (image == nullptr) {
-    InsertError(GL_INVALID_OPERATION, "No image found with the given ID");
-    return error::kNoError;
-  }
-
-  if (!image->BindTexImage(target)) {
-    image->CopyTexImage(target);
-  }
+  return BindTexImage2DCHROMIUMImpl(target, 0, imageId);
+}
 
-  return error::kNoError;
+error::Error
+GLES2DecoderPassthroughImpl::DoBindTexImage2DWithInternalformatCHROMIUM(
+    GLenum target,
+    GLenum internalformat,
+    GLint imageId) {
+  return BindTexImage2DCHROMIUMImpl(target, internalformat, imageId);
 }
 
 error::Error GLES2DecoderPassthroughImpl::DoReleaseTexImage2DCHROMIUM(