Give the media context small memory limits (same as compositor).

content/renderer/render_widget.cc

 // Copyright (c) 2012 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 "content/renderer/render_widget.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 743 matching lines @@
         frame_swap_message_queue_));
   }
 
   scoped_refptr<ContextProviderCommandBuffer> worker_context_provider =
       RenderThreadImpl::current()->SharedCompositorWorkerContextProvider();
   if (!worker_context_provider) {
     // Cause the compositor to wait and try again.
     return nullptr;
   }
 
-  gpu::SharedMemoryLimits limits;
   // The renderer compositor context doesn't do a lot of stuff, so we don't
   // expect it to need a lot of space for commands or transfer. Raster and
   // uploads happen on the worker context instead.
-  limits.command_buffer_size = 64 * 1024;
-  limits.start_transfer_buffer_size = 64 * 1024;
-  limits.min_transfer_buffer_size = 64 * 1024;
+  gpu::SharedMemoryLimits limits = gpu::SharedMemoryLimits::ForMailboxContext();
 
   // This is for an offscreen context for the compositor. So the default
   // framebuffer doesn't need alpha, depth, stencil, antialiasing.
   gpu::gles2::ContextCreationAttribHelper attributes;
   attributes.alpha_size = -1;
   attributes.depth_size = 0;
   attributes.stencil_size = 0;
   attributes.samples = 0;
   attributes.sample_buffers = 0;
   attributes.bind_generates_resource = false;
@@ skipping 1306 matching lines @@
 }
 
 float RenderWidget::GetOriginalDeviceScaleFactor() const {
   return
       screen_metrics_emulator_ ?
       screen_metrics_emulator_->original_screen_info().deviceScaleFactor :
       device_scale_factor_;
 }
 
 }  // namespace content