Makes BitmapUploader handle null GLES2Context

components/bitmap_uploader/bitmap_uploader.cc

 // Copyright 2015 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 "components/bitmap_uploader/bitmap_uploader.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 28 matching lines @@
 BitmapUploader::~BitmapUploader() {
 }
 
 void BitmapUploader::Init(shell::Connector* connector) {
   surface_ = window_->RequestSurface(mus::mojom::SurfaceType::DEFAULT);
   surface_->BindToThread();
   surface_->set_client(this);
 
   gles2_context_ = mus::GLES2Context::CreateOffscreenContext(
       std::vector<int32_t>(), connector);
-  DCHECK(gles2_context_);
+  // CreateOffscreenContext() may return null.
 }
 
 // Sets the color which is RGBA.
 void BitmapUploader::SetColor(uint32_t color) {
   if (color_ == color)
     return;
   color_ = color;
   if (surface_)
     Upload();
 }
 
 // Sets a bitmap.
 void BitmapUploader::SetBitmap(int width,
                                int height,
                                std::unique_ptr<std::vector<unsigned char>> data,
                                Format format) {
   width_ = width;
   height_ = height;
   bitmap_ = std::move(data);
   format_ = format;
   if (surface_)
     Upload();
 }
 
 void BitmapUploader::Upload() {
+  if (!gles2_context_)
+    return;
+
   const gfx::Rect bounds(window_->bounds().size());
 
   cc::CompositorFrame frame;
   // TODO(rjkroege): Support device scale factors other than 1.
   frame.metadata.device_scale_factor = 1.0f;
   frame.delegated_frame_data.reset(new cc::DelegatedFrameData());
   frame.delegated_frame_data->resource_list.resize(0u);
 
   const cc::RenderPassId render_pass_id(1, 1);
   std::unique_ptr<cc::RenderPass> pass = cc::RenderPass::Create();
@@ skipping 113 matching lines @@
     DCHECK_EQ(1, resource.count);
     gl->WaitSyncTokenCHROMIUM(resource.sync_token.GetConstData());
     uint32_t texture_id = resource_to_texture_id_map_[resource.id];
     DCHECK_NE(0u, texture_id);
     resource_to_texture_id_map_.erase(resource.id);
     gl->DeleteTextures(1, &texture_id);
   }
 }
 
 }  // namespace bitmap_uploader