libbacktrace: expose BacktraceMap's unwindstack::Memory.

Test: mma
Change-Id: Icd2b891b121b90d55e3ac45037a59c24221a2496

libbacktrace/UnwindStackMap.cpp

@@ -96,6 +96,10 @@ std::string UnwindStackMap::GetFunctionName(uintptr_t pc, uintptr_t* offset) {
   return name;
 }
 
+std::shared_ptr<unwindstack::Memory> UnwindStackMap::GetProcessMemory() {
+  return process_memory_;
+}
+
 //-------------------------------------------------------------------------
 // BacktraceMap create function.
 //-------------------------------------------------------------------------

libbacktrace/UnwindStackMap.h

@@ -35,6 +35,7 @@ class UnwindStackMap : public BacktraceMap {
   void FillIn(uintptr_t addr, backtrace_map_t* map) override;
 
   virtual std::string GetFunctionName(uintptr_t pc, uintptr_t* offset) override;
+  virtual std::shared_ptr<unwindstack::Memory> GetProcessMemory() override final;
 
   unwindstack::Maps* stack_maps() { return stack_maps_.get(); }
 

libbacktrace/include/backtrace/BacktraceMap.h

@@ -46,6 +46,10 @@ struct backtrace_map_t {
   std::string name;
 };
 
+namespace unwindstack {
+class Memory;
+}
+
 class BacktraceMap {
 public:
   // If uncached is true, then parse the current process map as of the call.
@@ -64,6 +68,7 @@ public:
 
   // Only supported with the new unwinder.
   virtual std::string GetFunctionName(uintptr_t /*pc*/, uintptr_t* /*offset*/) { return ""; }
+  virtual std::shared_ptr<unwindstack::Memory> GetProcessMemory() { return nullptr; }
 
   // The flags returned are the same flags as used by the mmap call.
   // The values are PROT_*.