Add a switch to Chromium to enable/disable 'image/webp' accept header.

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index 563b04958028e3fbb3360f92f11e7899b2d135a3..60c41b7753ae7f04b58012de6726851b41cea695 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -771,6 +771,9 @@ void RenderThreadImpl::EnsureWebKitInitialized() {
   WebRuntimeFeatures::enableSeamlessIFrames(
       command_line.HasSwitch(switches::kEnableExperimentalWebKitFeatures));
 
+  WebRuntimeFeatures::enableWebPInAcceptHeader(
+      command_line.HasSwitch(switches::kEnableWebPInAcceptHeader));
+
   FOR_EACH_OBSERVER(RenderProcessObserver, observers_, WebKitInitialized());
 
   devtools_agent_message_filter_ = new DevToolsAgentFilter();