[Tracing] Enable heap dumps with both type info and backtraces

base/trace_event/heap_profiler_allocation_context.h

Index: base/trace_event/heap_profiler_allocation_context.h
diff --git a/base/trace_event/heap_profiler_allocation_context.h b/base/trace_event/heap_profiler_allocation_context.h
index 6a46d03e73b644799b345563d4e6707e75aba6d5..a7f1e9dca9031a9e62a877226cb28ca27480b5ba 100644
--- a/base/trace_event/heap_profiler_allocation_context.h
+++ b/base/trace_event/heap_profiler_allocation_context.h
@@ -82,12 +82,12 @@ bool BASE_EXPORT operator==(const AllocationContext& lhs,
 namespace BASE_HASH_NAMESPACE {
 
 template <>
-struct hash<base::trace_event::Backtrace> {
+struct BASE_EXPORT hash<base::trace_event::Backtrace> {

[Primiano Tucci (use gerrit), 2015/12/09 17:03:59]

just doublechecking: does this need to be exported because you need it in the
unittests (which in component builds are a different link unit?)

[Ruud van Asseldonk, 2015/12/09 20:58:04]

content/child also uses it now. The |AllocationContext| hash, that is.
|Backtrace| doesn’t strictly need to be exported, but it was bad style because
it is in the headers, so putting this in a hash map outside of base would
compile perfectly fine and then fail to link. I should have exported this in the
first place, but I forgot. (And you missed it when reviewing :)

   size_t operator()(const base::trace_event::Backtrace& backtrace) const;
 };
 
 template <>
-struct hash<base::trace_event::AllocationContext> {
+struct BASE_EXPORT hash<base::trace_event::AllocationContext> {
   size_t operator()(const base::trace_event::AllocationContext& context) const;
 };