Make some tcmalloc constants truly const.

Change-Id: I84e036d5c71373ce3572d4b67b06fcadb25bb347
Reviewed-on: https://chromium-review.googlesource.com/777963
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517642}

third_party/tcmalloc/README.chromium

@@ -110,3 +110,4 @@ Modifications:
 - Changed kint64min to not depend on undefined behavior.
 - Fix potential missing nul character in symbol names produced by addr2line-pdb.
 - Remove superfluous size_t value >= 0 check.
+- Make kFooType in tcmalloc.cc truly const.

third_party/tcmalloc/chromium/src/tcmalloc.cc

@@ -818,13 +818,13 @@ class TCMallocImplementation : public MallocExtension {
   }
 
   virtual void GetFreeListSizes(vector<MallocExtension::FreeListInfo>* v) {
-    static const char* kCentralCacheType = "tcmalloc.central";
-    static const char* kTransferCacheType = "tcmalloc.transfer";
-    static const char* kThreadCacheType = "tcmalloc.thread";
-    static const char* kPageHeapType = "tcmalloc.page";
-    static const char* kPageHeapUnmappedType = "tcmalloc.page_unmapped";
-    static const char* kLargeSpanType = "tcmalloc.large";
-    static const char* kLargeUnmappedSpanType = "tcmalloc.large_unmapped";
+    static const char kCentralCacheType[] = "tcmalloc.central";
+    static const char kTransferCacheType[] = "tcmalloc.transfer";
+    static const char kThreadCacheType[] = "tcmalloc.thread";
+    static const char kPageHeapType[] = "tcmalloc.page";
+    static const char kPageHeapUnmappedType[] = "tcmalloc.page_unmapped";
+    static const char kLargeSpanType[] = "tcmalloc.large";
+    static const char kLargeUnmappedSpanType[] = "tcmalloc.large_unmapped";
 
     v->clear();