Add Web Resources usage to chrome://tracing.

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

Index: third_party/WebKit/Source/core/fetch/MemoryCache.h
diff --git a/third_party/WebKit/Source/core/fetch/MemoryCache.h b/third_party/WebKit/Source/core/fetch/MemoryCache.h
index 92664bd164a14164a5a4f453c3361ac3aa586616..a82632c2bca331d087e25cbb063aff2c1f44428e 100644
--- a/third_party/WebKit/Source/core/fetch/MemoryCache.h
+++ b/third_party/WebKit/Source/core/fetch/MemoryCache.h
@@ -28,6 +28,7 @@
 #include "core/CoreExport.h"
 #include "core/fetch/Resource.h"
 #include "core/fetch/ResourcePtr.h"
+#include "public/platform/WebMemoryDumpProvider.h"
 #include "public/platform/WebThread.h"
 #include "wtf/Allocator.h"
 #include "wtf/HashMap.h"
@@ -130,7 +131,7 @@ WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(blink::MemoryCacheLRUList);
 
 namespace blink {
 
-class CORE_EXPORT MemoryCache final : public GarbageCollectedFinalized<MemoryCache>, public WebThread::TaskObserver {
+class CORE_EXPORT MemoryCache final : public GarbageCollectedFinalized<MemoryCache>, public WebThread::TaskObserver, public WebMemoryDumpProvider {
     WTF_MAKE_NONCOPYABLE(MemoryCache);
 public:
     static MemoryCache* create();
@@ -233,6 +234,9 @@ public:
 
     void updateFramePaintTimestamp();
 
+    // WebMemoryDumpProvider implementation
+    bool onMemoryDump(WebMemoryDumpLevelOfDetail, WebProcessMemoryDump*) override;
+
 private:
     enum PruneStrategy {
         // Automatically decide how much to prune.