libchrome: Several upstreamable fixes from libchrome

base/debug/stack_trace_posix.cc

Index: base/debug/stack_trace_posix.cc
diff --git a/base/debug/stack_trace_posix.cc b/base/debug/stack_trace_posix.cc
index fc3ee14c7b9d60958ad6d6000d94cbc616b6c7df..5f7e5a80f6362eb7f7cb27ed7dffe7c642527444 100644
--- a/base/debug/stack_trace_posix.cc
+++ b/base/debug/stack_trace_posix.cc
@@ -66,7 +66,7 @@ const char kSymbolCharacters[] =
     "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";
 #endif  // !defined(USE_SYMBOLIZE) && defined(__GLIBCXX__)
 
-#if !defined(USE_SYMBOLIZE)
+#if !defined(__UCLIBC__) && !defined(USE_SYMBOLIZE)

[danakj, 2016/05/23 02:59:54]

Can you explain?

[Luis Héctor Chávez, 2016/05/24 15:27:52]

DemangleSymbols is only used when neither __UCLIBC__ nor USE_SYMBOLIZE are
defined.

 // Demangles C++ symbols in the given text. Example:
 //
 // "out/Debug/base_unittests(_ZN10StackTraceC1Ev+0x20) [0x817778c]"
@@ -76,7 +76,7 @@ void DemangleSymbols(std::string* text) {
   // Note: code in this function is NOT async-signal safe (std::string uses
   // malloc internally).
 
-#if defined(__GLIBCXX__) && !defined(__UCLIBC__)
+#if defined(__GLIBCXX__)
 
   std::string::size_type search_from = 0;
   while (search_from < text->size()) {
@@ -113,9 +113,14 @@ void DemangleSymbols(std::string* text) {
     }
   }
 
-#endif  // defined(__GLIBCXX__) && !defined(__UCLIBC__)
+#else

[danakj, 2016/05/23 02:59:54]

comment on what this is #else-ing

[Luis Héctor Chávez, 2016/05/24 15:27:52]

Done.

+

[danakj, 2016/05/23 02:59:54]

no need for the whitespace

[Luis Héctor Chávez, 2016/05/24 15:27:52]

Done.

+  // Avoid an unused warning.
+  (void)text;
+

[danakj, 2016/05/23 02:59:54]

ditto

[Luis Héctor Chávez, 2016/05/24 15:27:52]

Done.

+#endif  // defined(__GLIBCXX__)
 }
-#endif  // !defined(USE_SYMBOLIZE)
+#endif  // !defined(__UCLIBC__) && !defined(USE_SYMBOLIZE)
 
 class BacktraceOutputHandler {
  public: