Expose --disable-gpu-compositing browser arg to Blink

content/child/runtime_features.cc

 // Copyright 2013 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/child/runtime_features.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/feature_list.h"
@@ skipping 97 matching lines @@
 
   if (command_line.HasSwitch(switches::kEnableDisplayList2dCanvas))
     WebRuntimeFeatures::enableDisplayList2dCanvas(true);
 
   if (command_line.HasSwitch(switches::kDisableDisplayList2dCanvas))
     WebRuntimeFeatures::enableDisplayList2dCanvas(false);
 
   if (command_line.HasSwitch(switches::kForceDisplayList2dCanvas))
     WebRuntimeFeatures::forceDisplayList2dCanvas(true);
 
+  if (command_line.HasSwitch(switches::kDisableGpuCompositing) ||
+      command_line.HasSwitch(switches::kDisableGpu))

[danakj, 2016/10/04 21:41:27]

Sorry just noticed this but you don't need to check disable-gpu here. In that
case we won't be able to make a context. Similarly we dont check for that flag
here
https://cs.chromium.org/chromium/src/content/renderer/render_thread_impl.cc?r...

+    WebRuntimeFeatures::enableGpuCompositing(false);
+  else
+    WebRuntimeFeatures::enableGpuCompositing(true);
+
   if (command_line.HasSwitch(
       switches::kEnableCanvas2dDynamicRenderingModeSwitching))
     WebRuntimeFeatures::enableCanvas2dDynamicRenderingModeSwitching(true);
 
   if (command_line.HasSwitch(switches::kEnableWebGLDraftExtensions))
     WebRuntimeFeatures::enableWebGLDraftExtensions(true);
 
 #if defined(OS_MACOSX)
   bool enable_canvas_2d_image_chromium = command_line.HasSwitch(
       switches::kEnableGpuMemoryBufferCompositorResources) &&
@@ skipping 188 matching lines @@
   if (command_line.HasSwitch(switches::kDisableBlinkFeatures)) {
     std::vector<std::string> disabled_features = base::SplitString(
         command_line.GetSwitchValueASCII(switches::kDisableBlinkFeatures),
         ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
     for (const std::string& feature : disabled_features)
       WebRuntimeFeatures::enableFeatureFromString(feature, false);
   }
 }
 
 }  // namespace content