Use delete/delete[] rather than free/realloc in tracedump

Bug: 28587945
Change-Id: I62281a956503b4351a36d6798bcd61e408b448f6
diff --git a/tools/dmtracedump/tracedump.cc b/tools/dmtracedump/tracedump.cc
index f70e2c2..3afee6f 100644
--- a/tools/dmtracedump/tracedump.cc
+++ b/tools/dmtracedump/tracedump.cc
@@ -512,10 +512,10 @@
 void freeDataKeys(DataKeys* pKeys) {
   if (pKeys == nullptr) return;
 
-  free(pKeys->fileData);
-  free(pKeys->threads);
-  free(pKeys->methods);
-  free(pKeys);
+  delete[] pKeys->fileData;
+  delete[] pKeys->threads;
+  delete[] pKeys->methods;
+  delete pKeys;
 }
 
 /*
@@ -822,8 +822,8 @@
 DataKeys* parseKeys(FILE* fp, int32_t verbose) {
   int64_t offset;
   DataKeys* pKeys = new DataKeys();
-  memset(pKeys, 0, sizeof(DataKeys));
   if (pKeys == nullptr) return nullptr;
+  memset(pKeys, 0, sizeof(DataKeys));
 
   /*
    * We load the entire file into memory.  We do this, rather than memory-
@@ -865,9 +865,13 @@
     return nullptr;
   }
 
-  /* Reduce our allocation now that we know where the end of the key section is. */
-  pKeys->fileData = reinterpret_cast<char*>(realloc(pKeys->fileData, offset));
-  pKeys->fileLen = offset;
+  /*
+   * Although it is tempting to reduce our allocation now that we know where the
+   * end of the key section is, there is a pitfall. The method names and
+   * signatures in the method list contain pointers into the fileData area.
+   * Realloc or free will result in corruption.
+   */
+
   /* Leave fp pointing to the beginning of the data section. */
   fseek(fp, offset, SEEK_SET);
 
@@ -2607,7 +2611,7 @@
     if (gOptions.graphFileName != nullptr) {
       createInclusiveProfileGraphNew(dataKeys);
     }
-    free(methods);
+    delete[] methods;
   }
 
   freeDataKeys(dataKeys);