base: Remove the string logging from CHECK().

content/renderer/render_frame_proxy.cc

Index: content/renderer/render_frame_proxy.cc
diff --git a/content/renderer/render_frame_proxy.cc b/content/renderer/render_frame_proxy.cc
index fbb1c1718cdb1a5324ae325281e31f5b24d346c7..b822b46fdb0c39c54b372dac297fe50edd6fa574 100644
--- a/content/renderer/render_frame_proxy.cc
+++ b/content/renderer/render_frame_proxy.cc
@@ -187,7 +187,8 @@ RenderFrameProxy::RenderFrameProxy(int routing_id, int frame_routing_id)
       render_widget_(nullptr) {
   std::pair<RoutingIDProxyMap::iterator, bool> result =
       g_routing_id_proxy_map.Get().insert(std::make_pair(routing_id_, this));
-  CHECK(result.second) << "Inserting a duplicate item.";
+  // Inserting a duplicate item.
+  CHECK(result.second);
   RenderThread::Get()->AddRoute(routing_id_, this);
 }
 
@@ -214,7 +215,8 @@ void RenderFrameProxy::Init(blink::WebRemoteFrame* web_frame,
 
   std::pair<FrameMap::iterator, bool> result =
       g_frame_map.Get().insert(std::make_pair(web_frame_, this));
-  CHECK(result.second) << "Inserted a duplicate item.";
+  // Inserted a duplicate item.
+  CHECK(result.second);
 }
 
 void RenderFrameProxy::WillBeginCompositorFrame() {