[Tracing] Add hook to PartitionAlloc for heap profiling

third_party/WebKit/public/platform/WebMemoryDumpProvider.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WebMemoryDumpProvider_h
 #define WebMemoryDumpProvider_h
 
 #include "WebCommon.h"
 
 namespace blink {
 
 class WebProcessMemoryDump;
 
 // Used to specify the type of memory dump the WebMemoryDumpProvider should
 // generate on dump requests.
 enum class WebMemoryDumpLevelOfDetail {
     Light,
     Detailed
 };
 
 // Base interface to be part of the memory tracing infrastructure. Blink classes
 // can implement this interface and register themselves (see
 // 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.
     // WebMemoryDumpLevelOfDetail specifies the size of dump the embedders
     // should generate on dump requests. Embedders are expected to populate
     // the WebProcessMemoryDump* argument depending on the level and return true
     // 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 whether the current dump provider supports heap profiling.
+    // TODO(ruuda): Remove once wtf can depend on base and do bookkeeping in the
+    // provider itself.
+    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).
+    virtual void onHeapProfilingEnabled(AllocationHook* allocationHook, FreeHook* freeHook) {}
 };
 
 } // namespace blink
 
 #endif // WebMemoryDumpProvider_h