tracing: Report ResourceClients and the reason for not deletable for web-caches

third_party/WebKit/Source/core/fetch/ResourceClient.h

Index: third_party/WebKit/Source/core/fetch/ResourceClient.h
diff --git a/third_party/WebKit/Source/core/fetch/ResourceClient.h b/third_party/WebKit/Source/core/fetch/ResourceClient.h
index ae4b776270ecb7fd3bcf01586276deaa8a49a9c1..08be8fc5a35f59671ed693b8e47dca400ea76240 100644
--- a/third_party/WebKit/Source/core/fetch/ResourceClient.h
+++ b/third_party/WebKit/Source/core/fetch/ResourceClient.h
@@ -28,6 +28,7 @@
 #include "core/CoreExport.h"
 #include "platform/network/ResourceLoadPriority.h"
 #include "wtf/Forward.h"
+#include "wtf/text/WTFString.h"
 
 namespace blink {
 class Resource;
@@ -52,6 +53,9 @@ public:
 
     virtual ResourcePriority computeResourcePriority() const { return ResourcePriority(); }
 
+    // Name for debugging, e.g. shown in memory-infra.
+    virtual String debugName() const = 0;
+
 protected:
     ResourceClient() { }
 };