[Tracing] Add hook to PartitionAlloc for heap profiling

third_party/WebKit/public/platform/WebMemoryDumpProvider.h

Index: third_party/WebKit/public/platform/WebMemoryDumpProvider.h
diff --git a/third_party/WebKit/public/platform/WebMemoryDumpProvider.h b/third_party/WebKit/public/platform/WebMemoryDumpProvider.h
index df151e8297bd2e1e5a406a6f8703a4d8a6bdff2a..6ab4bbc732bd3882464288212f3c0d3cc96840cd 100644
--- a/third_party/WebKit/public/platform/WebMemoryDumpProvider.h
+++ b/third_party/WebKit/public/platform/WebMemoryDumpProvider.h
@@ -23,6 +23,11 @@ enum class WebMemoryDumpLevelOfDetail {
 // Platform::registerMemoryDumpProvider()) to dump stats for their allocators.
 class BLINK_PLATFORM_EXPORT WebMemoryDumpProvider {
 public:
+    // Function types for functions that can be called on alloc and free to do
+    // heap profiling.
+    typedef void AllocationHook(void* address, size_t);
+    typedef void FreeHook(void* address);
+
     virtual ~WebMemoryDumpProvider();
 
     // Called by the MemoryDumpManager when generating memory dumps.
@@ -32,6 +37,17 @@ public:
     // on success or false if anything went wrong and the dump should be
     // considered invalid.
     virtual bool onMemoryDump(WebMemoryDumpLevelOfDetail, WebProcessMemoryDump*) = 0;
+
+    // Because Blink cannot depend on base, heap profiling bookkeeping has to
+    // be done in the glue layer for now. This method allows the glue layer to
+    // detect for which dump provider it should do the bookkeeping.

[Primiano Tucci (use gerrit), 2015/10/19 21:32:04]

s/for which dump provider it should do the bookkeeping/whether the current dump
provider support heap profiling/

[haraken, 2015/10/20 00:14:19]

Add a TODO and mention that this should be removed once the dependency from wtf/
to base/ is added.

[Ruud van Asseldonk, 2015/10/20 11:43:57]

Done, though that does miss the fact that the glue layer can do bookkeeping for
only one dump provider.
Done.

+    virtual bool supportsHeapProfiling() { return false; }
+
+    // Called by the memory dump manager to enable heap profiling (with
+    // non-null hook functions) or called to disable heap profiling (with null
+    // pointers). This is a workaround for the fact that Blink cannot use

[Primiano Tucci (use gerrit), 2015/10/19 21:32:03]

Remove the "Ths is a workaround" part. You already explained that above, should
be enough.

[Ruud van Asseldonk, 2015/10/20 11:43:57]

Done.

+    // |base::trace_event::AllocationRegister| and do the bookkeeping itself.
+    virtual void onHeapProfilingEnabled(AllocationHook* allocationHook, FreeHook* freeHook) {}
 };
 
 } // namespace blink