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

gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.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_number_conversions.h"
 #include "ui/gl/gl_version_info.h"
 
 namespace gpu {
@@ skipping 3471 matching lines @@
     GLint location,
     const char* name) {
   glBindUniformLocationCHROMIUM(GetProgramServiceID(program, resources_),
                                 location, name);
   return error::kNoError;
 }
 
 error::Error GLES2DecoderPassthroughImpl::DoBindTexImage2DCHROMIUM(
     GLenum target,
     GLint imageId) {
-  if (target != GL_TEXTURE_2D) {
-    InsertError(GL_INVALID_ENUM, "Invalid target");
-    return error::kNoError;
-  }
+  return BindTexImage2DCHROMIUMImpl(target, 0, imageId);
+}
 
-  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 error::kNoError;
+error::Error
+GLES2DecoderPassthroughImpl::DoBindTexImage2DWithInternalformatCHROMIUM(
+    GLenum target,
+    GLenum internalformat,
+    GLint imageId) {
+  return BindTexImage2DCHROMIUMImpl(target, internalformat, imageId);
 }
 
 error::Error GLES2DecoderPassthroughImpl::DoReleaseTexImage2DCHROMIUM(
     GLenum target,
     GLint imageId) {
   if (target != GL_TEXTURE_2D) {
     InsertError(GL_INVALID_ENUM, "Invalid target");
     return error::kNoError;
   }
 
@@ skipping 466 matching lines @@
 }
 
 error::Error GLES2DecoderPassthroughImpl::DoSetEnableDCLayersCHROMIUM(
     GLboolean enable) {
   NOTIMPLEMENTED();
   return error::kNoError;
 }
 
 }  // namespace gles2
 }  // namespace gpu