Add Web Resources usage to chrome://tracing.

third_party/WebKit/Source/platform/SharedBuffer.cpp

Index: third_party/WebKit/Source/platform/SharedBuffer.cpp
diff --git a/third_party/WebKit/Source/platform/SharedBuffer.cpp b/third_party/WebKit/Source/platform/SharedBuffer.cpp
index d678a28fa5fb01dac6864ab458504c56fbf71b20..5d4894e0379c8149a3a82cadbb3929543dcbace4 100644
--- a/third_party/WebKit/Source/platform/SharedBuffer.cpp
+++ b/third_party/WebKit/Source/platform/SharedBuffer.cpp
@@ -27,6 +27,7 @@
 #include "config.h"
 #include "platform/SharedBuffer.h"
 
+#include "public/platform/WebProcessMemoryDump.h"
 #include "wtf/text/UTF8.h"
 #include "wtf/text/Unicode.h"
 
@@ -410,4 +411,18 @@ bool SharedBuffer::isLocked() const
     return m_buffer.isLocked();
 }
 
+void SharedBuffer::onMemoryDump(const String& dumpPrefix, WebProcessMemoryDump* memoryDump) const
+{
+    m_buffer.onMemoryDump(dumpPrefix + "/shared_buffer", memoryDump);
+
+    if (!m_buffer.size()) {
+        // If there is data in the segments, then it should have been allocated
+        // using fastMalloc.
+        const String dataDumpName = dumpPrefix + "/segments";
+        auto dump = memoryDump->createMemoryAllocatorDump(dataDumpName);
+        dump->AddScalar("size", "bytes", m_size);
+        memoryDump->AddSuballocation(dump->guid(), WTF::Partitions::allocatorPoolNameForTracing());
+    }
+}
+
 } // namespace blink