Print more info in MarkSweep::VerifyRoot

Refactored old root callback to use a new class called RootInfo.
RootInfo contains all the relevant info related to the root
associated with the callback. The MarkSweep::VerifyRoot function
now uses this info to print the StackVisitor's described location
if the GC root is of the type kRootJavaFrame.

Some other cleanup.

Example output:
E/art     (12167): Tried to mark 0x123 not contained by any spaces
E/art     (12167): Attempting see if it's a bad root
E/art     (12167): Found invalid root: 0x123 with type RootJavaFrame
E/art     (12167): Location=Visiting method
'void java.lang.Runtime.gc()' at dex PC 0xffffffff (native PC 0x0)
vreg=0

(cherry picked from commit 12f7423a2bb4bfab76700d84eb6d4338d211983a)

Bug: 18588862
Change-Id: Ic5a2781f704e931265ffb3621c2eab4b2e25f60f
diff --git a/runtime/debugger.h b/runtime/debugger.h
index 8f0db76..e79e8e4 100644
--- a/runtime/debugger.h
+++ b/runtime/debugger.h
@@ -28,6 +28,7 @@
 #include <string>
 #include <vector>
 
+#include "gc_root.h"
 #include "jdwp/jdwp.h"
 #include "jni.h"
 #include "jvalue.h"
@@ -87,7 +88,7 @@
   Mutex lock DEFAULT_MUTEX_ACQUIRED_AFTER;
   ConditionVariable cond GUARDED_BY(lock);
 
-  void VisitRoots(RootCallback* callback, void* arg, uint32_t tid, RootType root_type)
+  void VisitRoots(RootCallback* callback, void* arg, const RootInfo& root_info)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   void Clear();
@@ -122,7 +123,7 @@
   // single-step depth.
   int stack_depth;
 
-  void VisitRoots(RootCallback* callback, void* arg, uint32_t tid, RootType root_type)
+  void VisitRoots(RootCallback* callback, void* arg, const RootInfo& root_info)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   bool ContainsDexPc(uint32_t dex_pc) const;