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/transaction.cc b/runtime/transaction.cc
index 478066f..118c1a2 100644
--- a/runtime/transaction.cc
+++ b/runtime/transaction.cc
@@ -206,7 +206,7 @@
     it.second.VisitRoots(callback, arg);
     mirror::Object* old_root = it.first;
     mirror::Object* new_root = old_root;
-    callback(&new_root, arg, 0, kRootUnknown);
+    callback(&new_root, arg, RootInfo(kRootUnknown));
     if (new_root != old_root) {
       moving_roots.push_back(std::make_pair(old_root, new_root));
     }
@@ -233,7 +233,7 @@
     mirror::Array* old_root = it.first;
     CHECK(!old_root->IsObjectArray());
     mirror::Array* new_root = old_root;
-    callback(reinterpret_cast<mirror::Object**>(&new_root), arg, 0, kRootUnknown);
+    callback(reinterpret_cast<mirror::Object**>(&new_root), arg, RootInfo(kRootUnknown));
     if (new_root != old_root) {
       moving_roots.push_back(std::make_pair(old_root, new_root));
     }
@@ -396,7 +396,7 @@
       mirror::Object* obj =
           reinterpret_cast<mirror::Object*>(static_cast<uintptr_t>(field_value.value));
       if (obj != nullptr) {
-        callback(&obj, arg, 0, kRootUnknown);
+        callback(&obj, arg, RootInfo(kRootUnknown));
         field_value.value = reinterpret_cast<uintptr_t>(obj);
       }
     }
@@ -441,7 +441,7 @@
 }
 
 void Transaction::InternStringLog::VisitRoots(RootCallback* callback, void* arg) {
-  callback(reinterpret_cast<mirror::Object**>(&str_), arg, 0, kRootInternedString);
+  callback(reinterpret_cast<mirror::Object**>(&str_), arg, RootInfo(kRootInternedString));
 }
 
 void Transaction::ArrayLog::LogValue(size_t index, uint64_t value) {