Add Web Resources usage to chrome://tracing.

third_party/WebKit/Source/platform/PurgeableVector.cpp

Index: third_party/WebKit/Source/platform/PurgeableVector.cpp
diff --git a/third_party/WebKit/Source/platform/PurgeableVector.cpp b/third_party/WebKit/Source/platform/PurgeableVector.cpp
index 01cb41f2d68ba3eb8369ba8546c29d8ccc748521..940478803cfcfe75963424f5d4ac4cf02e1a56c1 100644
--- a/third_party/WebKit/Source/platform/PurgeableVector.cpp
+++ b/third_party/WebKit/Source/platform/PurgeableVector.cpp
@@ -33,6 +33,7 @@
 
 #include "public/platform/Platform.h"
 #include "public/platform/WebDiscardableMemory.h"
+#include "public/platform/WebProcessMemoryDump.h"
 #include "wtf/Assertions.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassOwnPtr.h"
@@ -79,6 +80,19 @@ void PurgeableVector::reserveCapacity(size_t capacity)
     moveDataFromDiscardableToVector();
 }
 
+void PurgeableVector::onMemoryDump(const String& dumpName, WebProcessMemoryDump* memoryDump) const
+{
+    if (m_discardable) {
+        WebMemoryAllocatorDump* dump = memoryDump->createDiscardableMemoryAllocatorDump(dumpName, m_discardable.get());

[haraken, 2015/09/29 02:44:48]

Would you add a TODO?

TODO(tasak): The discardable memory is locked (i.e., not discardable) while
someone keeps a ResourcePtr to the Resource. We shouldn't count the memory as
discardable.

[ssid, 2015/09/29 11:06:37]

The locked size of the discardable memory is added in the discardable memory
manager soon. So, it will display if the memory is locked or not.
(crbug.com/529943).
Though the memory is locked, it is still considered as discardable memory as
long as the memory is allocated using allocateWebDiscardable() api.

I am currently working on showing the locked part of discardable.

+        dump->AddScalar("discardable_size", "bytes", m_discardableSize);
+    }
+    if (m_vector.size() > 0) {

[haraken, 2015/09/29 02:44:48]

It is not possible that both m_discardable and m_vector are used at the same
time. See the comment in PurgeableVector.h.

Can we change this to 'else'? Also it would be better to add an assert to check
that there can't be data in both m_discardable and m_vector.

[ssid, 2015/09/29 11:06:37]

I see. Thanks. Made it else.

+        WebMemoryAllocatorDump* dump = memoryDump->createAllocatorDump(dumpName);
+        dump->AddScalar("size", "bytes", m_vector.size());
+        memoryDump->AddSuballocation(dump->guid(), String(WTF::Partitions::allocatorPoolNameForTracing()));
+    }
+}
+
 void PurgeableVector::moveDataFromDiscardableToVector()
 {
     if (m_discardable) {